WO2018061923A1 - Wood laminate material and method for manufacturing same - Google Patents

Wood laminate material and method for manufacturing same Download PDF

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Publication number
WO2018061923A1
WO2018061923A1 PCT/JP2017/033872 JP2017033872W WO2018061923A1 WO 2018061923 A1 WO2018061923 A1 WO 2018061923A1 JP 2017033872 W JP2017033872 W JP 2017033872W WO 2018061923 A1 WO2018061923 A1 WO 2018061923A1
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WO
WIPO (PCT)
Prior art keywords
strand
density
wood
layers
layer
Prior art date
Application number
PCT/JP2017/033872
Other languages
French (fr)
Japanese (ja)
Inventor
克仁 大島
一輝 坂本
一紘 平田
浩仁 長岡
康志 杉尾
Original Assignee
大建工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 大建工業株式会社 filed Critical 大建工業株式会社
Priority to CA3019340A priority Critical patent/CA3019340C/en
Priority to CN201780020304.6A priority patent/CN108883544A/en
Priority to US16/088,904 priority patent/US11260630B2/en
Priority to EP17855878.9A priority patent/EP3520977A4/en
Priority to JP2018518676A priority patent/JP6469318B2/en
Publication of WO2018061923A1 publication Critical patent/WO2018061923A1/en
Priority to US17/580,790 priority patent/US20220134715A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
    • B32B21/02—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board the layer being formed of fibres, chips, or particles, e.g. MDF, HDF, OSB, chipboard, particle board, hardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
    • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27N—MANUFACTURE BY DRY PROCESSES OF ARTICLES, WITH OR WITHOUT ORGANIC BINDING AGENTS, MADE FROM PARTICLES OR FIBRES CONSISTING OF WOOD OR OTHER LIGNOCELLULOSIC OR LIKE ORGANIC MATERIAL
    • B27N3/00—Manufacture of substantially flat articles, e.g. boards, from particles or fibres
    • B27N3/08—Moulding or pressing
    • B27N3/10—Moulding of mats
    • B27N3/14—Distributing or orienting the particles or fibres
    • B27N3/143—Orienting the particles or fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
    • B32B21/04—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board comprising wood as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B21/042—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board comprising wood as the main or only constituent of a layer, which is next to another layer of the same or of a different material of wood
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
    • B32B21/13—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board all layers being exclusively wood
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
    • B32B21/14—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board comprising wood board or veneer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/10—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
    • B32B37/16—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with all layers existing as coherent layers before laminating
    • B32B37/18—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with all layers existing as coherent layers before laminating involving the assembly of discrete sheets or panels only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/16—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer formed of particles, e.g. chips, powder or granules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/03—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers with respect to the orientation of features
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/546—Flexural strength; Flexion stiffness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/72—Density
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/732—Dimensional properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2317/00—Animal or vegetable based
    • B32B2317/16—Wood, e.g. woodboard, fibreboard, woodchips
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2419/00—Buildings or parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2605/00—Vehicles
    • B32B2605/003—Interior finishings

Definitions

  • the present invention relates to a wood laminate material that is integrated in a state where a plurality of wood material layers made of wood material are laminated, and a method for manufacturing the same.
  • Patent Document 1 discloses a large OSB plate having a maximum density of 700 kg / m 3 , a length of at least 7 m, and a bending elastic modulus in the main load direction of at least 7000 N / mm 2. ing.
  • Patent Document 2 discloses a technique in which a strand material formed by orienting and stacking wood material pieces and pressurizing and heating is used as a joist or foundation.
  • the density distribution in the thickness direction of the board may be non-uniform. found. If the density distribution is not uniform, the low density portion tends to be weak in strength. In addition, the portion having a low density has a higher water absorption and the water resistance is inferior than the portion having a high density. As a result of the uneven density distribution, the strength and water resistance are regulated by the low density portion, and there is a problem that sufficient strength and water resistance cannot be obtained.
  • An object of the present invention is to obtain a wood laminate material having high strength and high water resistance by adjusting the density distribution in the lamination direction in a wood laminate material in which a plurality of wood materials are laminated. .
  • it is possible to prevent a decrease in productivity when manufacturing the wood laminate, and to change variations in the properties of the wood laminate. There is to do.
  • the density distribution in the stacking direction of the wood laminate is made substantially constant, and the strength and water resistance of the wood laminate are increased.
  • the density distribution in the stacking direction of the wood material layer is substantially constant.
  • the density distribution in the stacking direction of the wood laminate is substantially constant.
  • the strength and water resistance are regulated by the low-density portion, but such a problem does not occur in the wood laminate according to the present invention. . Therefore, a wood laminate having high strength and high water resistance can be realized.
  • the wood material density may be less 300 kg / m 3 or more and 1100 kg / m 3 of, more preferably set to 300 Kg / m 3 or more and 800 Kg / m 3 or less.
  • the density of the wooden material is set to 300 kg / m 3 or more, the thickness of the laminated body necessary for forming the wooden laminated material having the same density and the same strength (the laminated body before the laminated body is integrated). (Thickness) can be reduced.
  • the thickness of a laminated body can be made thin, the workability
  • strength can be made low.
  • the thickness of the plurality of wood material layers may gradually increase from the inner side to the outer side in the stacking direction.
  • the thickness of the outer layer that is easily affected by the load, impact, humidity, and the like becomes thicker than that of the inner layer, so that the performance of the wooden laminated material against the external environment can be improved.
  • the densified wood material layer is used to increase the density of the wood laminates. Realized high strength and high water resistance.
  • the plurality of wood material layers includes at least one high-density wood material layer having a higher density than other wood material layers, and a low-density wood material layer composed of the other wood material layers.
  • the “density of the wood material layer” means the density of the aggregate if the wood material is a cut piece, and the density of the veneer itself if the wood material is a single plate. Yes.
  • At least one of the plurality of wood material layers is a high-density wood material layer, and the other layers are low-density wood material layers. High strength and high water resistance can be realized.
  • the press time by the press machine is shortened, the press pressure is lowered, the productivity can be improved, and the puncture at the time of molding can be prevented.
  • At least one wood material layer is a high-density wood material layer
  • a layer to be a high-density wood material layer can be selected as necessary from a plurality of wood material layers. By changing the position of the wood material layer, various variations can be obtained as the characteristics of the wood laminate.
  • the wood material layers located at both ends of the wood material layer in the stacking direction may be high-density wood material layers.
  • the wood layer at both ends in the stacking direction of the wood layer is a high-density wood layer, and the density is higher than other parts, so that the bending strength of the wood laminate can be increased, and the wood The water resistance performance of the front and back portions of the laminated material can be improved.
  • the wood material layer located in the middle part of the wood material layer in the stacking direction may be a high density wood material layer.
  • the wood material layer in the middle direction of the wood material layer is a high-density wood material layer, and the wood material layer located at the other part (both ends of the wood material layer in the lamination direction)
  • the density is higher than. Therefore, the density distribution in the stacking direction of the wood laminate can be made uniform as much as the density of the intermediate portion is increased.
  • a high-density wood material layer is arrange
  • the wood material layer located in the portion excluding both ends and the center of the wood material layer in the stacking direction may be a high-density wood material layer.
  • the wood material layer located in the portion excluding both ends and the center portion in the stacking direction of the wood material layer is a high density wood material layer, and the wood material layer located in the both ends and the center portion in the stacking direction is Low density. Therefore, the press pressure at the time of molding can be reduced by the low-density layers on the front and back sides of the wood laminate, and the nail pulling resistance (force) in the wood laminate can be increased by the high-density wood material layer.
  • each wood material layer may extend in the same direction, and the wood material fibers of adjacent wood material layers may extend in a direction intersecting or parallel to each other.
  • the fibers extend in the same direction and “the fibers extend in the parallel direction” are not limited to those in which the fibers of the wood material are oriented in the same direction, and the fibers are inclined to some extent.
  • a concept that includes A wood material in which the fibers are inclined by, for example, about 20 ° with respect to a predetermined reference direction may be included.
  • “extending in the direction in which the fibers cross each other” is not limited to those in which the fibers are oriented in the orthogonal direction to each other, but includes a wood material that is inclined, for example, by about 20 ° with respect to the orthogonal direction orthogonal to the reference direction. It may be.
  • the fibers of the wood material extend in the direction intersecting each other in the adjacent wood material layer, compared to the case where the fiber extends in the same direction over the entire wood material layer, there are various High strength can be achieved against the action of force from any direction.
  • the difference in strength due to the difference in the fiber direction becomes more remarkable as the number of laminated wood material layers increases.
  • the strength may vary depending on the direction in which the force is applied, but this does not occur.
  • the fibers of the wood material in the front surface layer and the back surface layer of the plurality of wood material layers may extend in the same direction.
  • the number of wooden material layers may be an odd number.
  • the wooden laminated material is obtained by laminating an odd number of wooden material layers, and the same performance can be obtained on both the front surface side and the back surface side of the wooden laminated material as described above.
  • the plurality of wood material layers may be laminated so that the density distribution by the plurality of wood material layers is plane-symmetric with respect to the center position in the lamination direction.
  • the wood material may be a strand made of a cut piece. By doing so, it is possible to realize a strand material having a high strength and a high water resistance, or a strand material having a high productivity and a variation in characteristics.
  • a method of manufacturing a wood laminate a plurality of wood materials made of cut pieces or single plates are stacked, so that a plurality of wood material layers are relative to each other, and at least one wood material layer is relative to other wood material layers. Characterized in that it comprises a laminating process for forming a high-density wood material having a high density and a molding process for integrally molding a plurality of wood material layers formed in this laminating process. To do.
  • the density distribution in the stacking direction after the molding process is adjusted by including a layer composed of a high-density wood material having a relatively higher density than the other wood material layers as the wood material layer.
  • the density distribution in the stacking direction of the wood laminate can be made substantially constant by optimizing the place where the wood material layer composed of the high-density wood is inserted.
  • the density distribution in the stacking direction of the wood laminate in which a plurality of wood materials made of cutting pieces or single plates are laminated is adjusted, and the density distribution in the stacking direction is substantially reduced.
  • the density distribution in the stacking direction is made different, and at least one of the plurality of wood material layers is a high density wood material layer having a higher density than other wood material layers, thereby providing high strength and high water resistance performance. Therefore, it is possible to improve the productivity by increasing the density of only the wood material layer that needs to be.
  • various variations can be obtained as the characteristics of the wood laminate by changing the layer to be the high-density wood material layer.
  • FIG. 1 is a perspective view schematically showing a laminated structure of strand boards according to Embodiment 1 of the present invention.
  • FIG. 2 is a perspective view schematically showing a first example of a strand board according to Embodiment 2 of the present invention.
  • FIG. 3 is a cross-sectional view schematically showing a layered state of strand layers in the first example of the strand board according to the second embodiment.
  • FIG. 4 is a view corresponding to FIG. 3 showing a second example of the strand board.
  • FIG. 5 is a view corresponding to FIG. 3 showing a third example of the strand board.
  • FIG. 6 is a view corresponding to FIG. 3 showing a fourth example of the strand board.
  • FIG. 7 is a view corresponding to FIG.
  • FIG. 10 is a cross-sectional view illustrating the strand board of Example 1 according to the first embodiment.
  • FIG. 11 is a diagram showing test results of Examples 1 and 2 and Comparative Examples 1 and 2.
  • FIG. 12 is a diagram illustrating the density distribution of the strand board according to the first embodiment.
  • FIG. 13 is a diagram showing the density distribution of the strand board according to Comparative Example 1.
  • FIG. 14 is a diagram illustrating the results of bending tests of Examples 1 and 2 and Comparative Example 1 according to Embodiment 2 together with other physical properties.
  • FIG. 15 is a diagram illustrating density distributions in Examples 1 and 2 and Comparative Example 1 in the thickness direction (stacking direction).
  • FIG. 16 is a diagram showing the results of the bending test and boiling test of Example 3 and Comparative Example 2 together with other physical properties.
  • FIG. 17 is a diagram showing the density distribution in the thickness direction (stacking direction) of Example 3 and Comparative Example 2.
  • FIG. 18 is a diagram showing the results of the bending test and boiling test of Example 4 and Comparative Example 3 together with other physical properties.
  • FIG. 19 is a diagram showing the results of the nail pull-out test of Example 4 and Comparative Example 4 together with other physical properties.
  • FIG. 20 is a diagram showing the density distribution in the thickness direction (stacking direction) of Example 4 and Comparative Example 3.
  • FIG. 1 schematically shows a strand board B as a wood laminate according to Embodiment 1 of the present invention.
  • the strand board B is composed of strand layers 1, 1,... As odd-numbered layers (5 layers in FIG. 1), and the thickness of the strand layers 1, 1,. Shows an example where all are equal. That is, when the upper side in FIG. 1 is the front side and the lower side is the back side, the thickness w1 of the front and back strand layers 1, 1 and the thickness w2, w3 of the three intermediate strand layers 1, 1,. , W2 are the same.
  • the number of layers of the strand layers 1 in the strand board B is not limited to an odd number layer, and may be an even number layer. Moreover, it is not limited to five layers, and may be four layers or less or six layers or more.
  • Each strand layer 1 is composed of an aggregate in which a large number of strands 5, 5,... (Woody material) as cutting pieces obtained from wood or the like are in an aggregated state.
  • a plurality of strand layers 1, 1,... Are formed by laminating and integrating the strands 5, 5,.
  • Each strand 5 is, for example, a thin plate or a piece having a length along the fiber direction of 150 to 200 mm, a width of 15 to 25 mm, and a thickness of about 0.3 to 2 mm.
  • the tree species used for the strand 5 is not particularly limited, and for example, a southern ocean tree or a broad-leaved tree may be used, or other tree species may be used. Specifically, for example, fur materials such as cedar, hinoki and bay pine, acacia, aspen, poplar, pine (hard pine, soft pine, attapine, radiata pine, etc.), birch, rubber (rubber tree), etc. However, it is not limited to these tree species, and various tree species can be used.
  • Various tree species include sawara, hiba, kayak, cocoon, cocoon, various pine, paulownia, cocoon, cocoon (white birch), vertebra, beech, cocoon, cocoon, cocoon, cocoon, cocoon, zelkova and other domestic timber, rice North American wood such as cypress, rice cypress, rice cedar, rice bran, spruce, rice bran, redwood, etc.
  • rice North American wood such as cypress, rice cypress, rice cedar, rice bran, spruce, rice bran, redwood, etc.
  • There are other external materials such as South Seawood, Balsa, Cedro, Mahogany, Lignumbaita, Acacia Mangum, Mediterranean Pine, bamboo, Kouliang, Chamelele, etc. Any material can be used.
  • the density is about 300 ⁇ 800kg / m 3, more preferably 430 ⁇ 700kg / m 3.
  • the density is 300 kg / m 3 or less, the thickness of the laminated mat necessary for forming the strand board B having the same density and the same strength is increased, and the hot-pressing process in the press molding process described later is applied. This is because it is necessary to increase the press pressure.
  • the density of the strand 5 may exceed 800 kg / m 3 , it is difficult to easily obtain such a strand 5. That is, if the strand 5 exceeding 800 kg / m 3 can be easily obtained, the upper limit value of the density is not limited to 800 kg / m 3 and may be a higher value.
  • the water content of the strand 5 is preferably about 2 to 20%, more preferably 2 to 8%.
  • the water content is less than 2%, it takes time for softening in the hot-pressing process in the press molding process, the press time becomes longer, and the strength may be lowered.
  • the water content of the strand 5 exceeds 20%, it takes time to heat and compress in the same hot press process, and it becomes easy to puncture, and further, the curing of the adhesive is inhibited and the strength may be lowered. It is.
  • the strands 5, 5,... are oriented so that the fiber direction (longitudinal direction of the strands 5) along the fibers (not shown) is along a predetermined direction.
  • the fibers of the strands 5, 5,... Do not necessarily have to face the same direction in each strand layer 1.
  • the plurality of strand layers 1, 1,... are stacked and integrated so that the fibers of the strands 5, 5,. That is, in FIG. 1, in the strand layer 1 (upper layer in FIG. 1) and the back strand layer 1 (lower layer in FIG. 1), the strands 5, 5, and 5 constituting these layers 1 and 1 are formed.
  • the fiber directions of ... extend along the same direction.
  • the density distribution of the strand layer 1 in the strand board B in the stacking direction is substantially constant.
  • the plurality of strand layers 1, 1,... Are laminated so that the density distribution by the plurality of strand layers 1, 1,.
  • This manufacturing method includes a strand generation step, a strand pretreatment step, an adhesive application step, a lamination step (mat formation step), and a press molding step.
  • strand production process In the manufacturing method of the strand board B, first, a strand generating step for obtaining a large number of strands 5, 5,... (Cut pieces such as wood) is performed.
  • strands 5, 5,... are generated by cutting raw wood such as logs and thinned wood with a cutting machine.
  • the strands 5, 5,... May be generated from scraps or waste materials generated at a construction site or the like, or may be generated from waste pallet materials.
  • This pre-treatment is for enabling low-pressure pressing with a low press pressure of, for example, about 4 N / mm 2 in the post-forming press forming step.
  • the physical treatment method, the high-frequency treatment method, the high-temperature and high-pressure treatment method, At least one of a water pressure treatment method, a degassing / dehydration repeated treatment method, a chemical treatment method, or the like is used.
  • the physical treatment method is a method of physically compressing the strand 5, and includes a roll press treatment method, a beating treatment method, a flat plate press method, and the like.
  • the roll press treatment method is a linear compression method, and although not shown, a large number of strands 5, 5,...
  • the heating temperature is room temperature to 200 ° C.
  • the clearance between the hot-pressing rolls is about 0.1 to 0.4 mm
  • the feed rate is about 50 m / min
  • the compression rate is about 20 to 60%.
  • the strands 5 are compressed without breaking, and the densified strands 5 are obtained.
  • the beating method is a point compression method, and, like the metal forging process, the strands 5 are struck and compressed and deformed by a plurality of continuously arranged spring hammers.
  • the strands 5 are compressed and densified without breaking.
  • the flat plate pressing method is a surface compression method, in which strands 5, 5,.
  • the pressing conditions are, for example, a temperature of 120 ° C. and a pressing pressure of about 4 N / mm 2 for about 5 minutes. Even in this method, the strands 5 are compressed and densified without breaking.
  • the high-frequency treatment method is a method in which the strand 5 as a dielectric (non-conductor) is irradiated with high-frequency electromagnetic waves (high-frequency) between electrodes or the like, and the strand 5 is dielectrically heated from the inside to be softened.
  • This method enables low-pressure pressing with a low pressing pressure in the post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
  • the high-temperature and high-pressure treatment method is a method in which the strand 5 is put in a pressure vessel and a high temperature and a high pressure are applied to damage and soften the cell wall of the strand 5 (woody material).
  • the treatment conditions are, for example, a temperature of 180 ° C. and a pressure of about 10 Bar for about 2 minutes.
  • This method also enables low-pressure pressing with a low pressing pressure in a post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
  • the high water pressure treatment method is a method in which the strand 5 is uniformly formed in a mesh material such as a wire mesh and fine scratches are formed on the surface of the strand 5 with high-pressure water of about 200 MPa through the mesh material. As a result, it is possible to obtain a softened strand 5 caused by fine breakage.
  • the degassing / dehydration repeated treatment method is such that the strand 5 is saturated and then charged into a batch-type kettle, and the inside of the kettle is evacuated under reduced pressure to release moisture from the strand 5.
  • This is a method of promoting the softening by promoting the destruction of the cell wall of 5 (wood material).
  • This method also enables low-pressure pressing with a low pressing pressure in a post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
  • the chemical treatment method is a method in which, for example, sodium hydroxide or the like is added to the strand 5 to perform alkali treatment, thereby promoting plasticization of the strand 5 itself and softening it.
  • This method also enables low-pressure pressing with a low pressing pressure in a post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
  • the state after treatment is maintained by drying the strand 5 as necessary after treatment.
  • an adhesive application step of applying an adhesive to the strands 5, 5, For example, an isocyanate-based adhesive can be used.
  • an amine-based adhesive such as a phenol resin, a urea resin, or a melamine resin may be used.
  • a large number of strands 5, 5,... Coated with an adhesive are stacked until the thickness becomes, for example, about 7 to 12 mm while the fibers are oriented so as to face a predetermined reference direction by a mat forming apparatus or the like.
  • a strand assembly having a certain thickness is formed.
  • the thickness of the strand aggregate is not limited to the above value, and may be less than 7 mm or more than 12 mm.
  • the strand assembly is repeated until the desired number of layers (for example, 5 layers) is reached, and the fiber directions of the strands 5, 5,. . In this way, a laminated mat is formed.
  • the desired number of layers for example, 5 layers
  • the thickness of the five-layer laminate mat is, for example, about 35 to 60 mm.
  • the number of layers of the strand aggregate in the laminated mat is determined according to the number of layers of the strand board B. Therefore, it may be 4 layers or less or 6 layers or more.
  • the density of the strands 5, 5,... Constituting the strand layer 1 may be the same or different from each other among the plurality of strand layers 1, 1,.
  • the laminated mat is subjected to a hot-pressing process at a predetermined pressure and temperature by a hot-pressing apparatus and integrally molded.
  • the press pressure related to this hot press process is, for example, 2 to 4 N / mm 2
  • the press time is, for example, 10 to 20 minutes.
  • the press time varies depending on the thickness of the strand board B (finished product), and may be completed in less than 10 minutes, or may be required in 20 minutes or more.
  • the strand board B having a density of 750 to 950 kg / m 3 and a bending strength of 80 to 150 N / mm 2 is integrally formed.
  • the press pressure of the hot press in the press molding process is set to be low to 2-4 N / mm 2 . Therefore, a high-density and high-strength strand board B can be obtained without using a special high-pressure press.
  • the strand board B has each the front side and the back side of the strand board B. Performances such as load resistance and impact resistance can be aligned to the same extent. That is, equivalent performance can be obtained on the front and back of the strand board B. This produces the merit that the strand board B can be used without worrying about its front and back.
  • the board performance such as strength characteristics in the thickness direction and water resistance characteristics of the strand board B can be made uniform.
  • the same performance can be obtained on both the front side and the back side of the strand board B. It can be used regardless of the front and back of board B (without concern).
  • the same performance can be obtained on both the front side and the back side of the strand board B as described above.
  • the strands 5, 5,... Produced in the strand producing step preferably have a density of 430 to 700 kg / m 3 and a moisture content of 2 to 20%.
  • the strands 5, 5,... Obtained by the strand generation step deviate from the preferable characteristics, the strands 5, 5,.
  • the strands 5, 5,... Having desired characteristics are selected from the strands after the cutting process by a sorting machine or the like, and the subsequent strand generation process using the selected strands 5, 5,.
  • the strand pretreatment step, the adhesive application step, the lamination step (mat formation step), and the press molding step may be performed.
  • the substantial water content and density of the strands 5, 5,... May be adjusted by devising the composition and application method of the adhesive used in the adhesive application step.
  • a predetermined press process may be performed in the hot press process in the press molding process or before the hot press process.
  • the substantial moisture content of the strands 5, 5,. It is adopted to increase the substantial density of.
  • FIG. 2 to 8 show a second embodiment of the present invention (note that the same parts as those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted).
  • 2 to 8 show a plurality of examples of the strand board B as the wood laminate according to the second embodiment, and FIGS. 2 and 3 show a first example of the strand board B.
  • FIG. 4 shows a second example
  • FIG. 5 shows a third example
  • FIG. 6 shows a fourth example
  • FIG. 7 shows a fifth example
  • FIG. 8 shows a sixth example.
  • the strand board B includes a plurality of (odd number) wood layers 1, 1,.
  • Each strand layer 1 is composed of an aggregate of a large number of strands 5, 5,... (Wooden material) as cutting pieces, and a plurality of the aggregates of the strands 5, 5,.
  • a plurality of strand layers 1, 1,... Are formed.
  • the upper side of FIGS. 3 to 8 is the front side of the strand board B and the lower side is the back side, and the strand layers 1, 1,... Are in order from the front side to the back side.
  • the numbers are represented by circled numbers in FIGS.
  • the density of each strand 5 is preferably about 300 to 1100 kg / m 3 .
  • the density is less than 300 kg / m 3, it is necessary to increase the thickness of the laminated mat necessary for producing the high-density strand layer 1 and to increase the press pressure related to the hot press process in the press forming process. Because there is.
  • the density of the strand 5 may exceed 1100 kg / m 3 , but it is difficult to easily obtain such a strand 5. That is, if the strand 5 exceeding 1100 kg / m 3 can be easily obtained, the upper limit value of the density is not limited to 1100 kg / m 3, and may be a higher value.
  • the strands 5, 5,... are oriented in each strand layer 1 so that the fiber direction, which is the direction along the fiber, is a predetermined direction.
  • the fibers of the strands 5, 5,... are oriented in the same direction, that is, the fiber directions of the oriented strands 5 need to be parallel.
  • the strand 5 in which the fiber direction is inclined to some extent with respect to the predetermined reference direction may be included.
  • the strand 5 in which the orientation direction is inclined by about 20 ° with respect to the reference direction may be included.
  • the second embodiment unlike the first embodiment, at least one of the odd-numbered strand layers 1, 1,... In the strand board B has a higher density than the other strand layers 1b.
  • the remaining strand layer 1b is a low-density strand layer.
  • the “density of the strand layer” in the second embodiment refers not to the density of the strand 5 itself but to the density of the strand layer 1 itself that is an aggregate thereof.
  • the high-density strand layer 1a is represented by a dense point set
  • the low-density strand layer 1b is represented by a coarse point set.
  • the strand board B includes first to fifth five strand layers 1, 1,... Each of the strand layers 1, 1,... Is laminated and integrated with the adjacent strand layer 1 so that the fibers of the strands 5 and 5 extend in directions orthogonal to each other.
  • the fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end in FIG. 3 located at the front end of the strand board B and the fifth strand layer 1 at the lower end in FIG. is there.
  • Two of the five strand layers 1, 1,... are high-density strand layers 1a whose density is higher than the other three layers, and the latter is a low-density strand layer 1b. .
  • the two high-density strand layers 1a and 1a have the same density, for example, 1000 kg / m 3 (average value).
  • the three low-density strand layers 1b, 1b,... Have the same density, for example, 800 kg / m 3 .
  • the density of the low-density strand layer 1b is approximately the same as the density of the strand board that is usually formed.
  • the first strand layer 1 located at the front side end of the strand board B, the fifth strand layer 1 located at the back side end, and the third strand layer 1 located at the center in the thickness direction are all. It is the low density strand layer 1b. Both the second and fourth strand layers 1 and 1 located at portions excluding the front and back end portions and the central portion in the thickness direction are high-density strand layers 1a.
  • the five strand layers 1, 1,... Have different thicknesses and are divided into three.
  • the thickness of each of the first and fifth strand layers 1 and 1 (low-density strand layer 1b) is, for example, 25% of the total thickness of the strand board B, and the second and fourth strand layers 1 and 1 (
  • Each thickness of the high-density strand layer 1a) occupies, for example, 20%
  • the thickness of the third strand layer 1 (low-density strand layer 1b) occupies, for example, 10%.
  • the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 40%.
  • the five strand layers 1, 1,... Are arranged so that the density distribution by the strand layers 1, 1,... Is plane-symmetric with respect to the lamination position of the strand board B, that is, the center position in the thickness direction. Are stacked.
  • the total thickness of the strand board B is 28 mm, for example.
  • a method for manufacturing the strand board B according to the second embodiment will be described. This manufacturing method is the same when manufacturing not only the strand board B of the first example but also the strand boards B of the second to sixth examples.
  • the manufacturing method of the second embodiment is basically the same as that of the first embodiment. Therefore, description of the same part as Embodiment 1 is abbreviate
  • this manufacturing method has a strand production
  • the strand pretreatment process, the adhesive application process, and the press molding process are the same as those in the first embodiment.
  • the mat forming process another strand aggregate is stacked on the strand aggregate.
  • the density of each strand 5 of the strand aggregate to be the high-density strand layer 1a is set higher than the density of the strand 5 of the strand aggregate that becomes the low-density strand layer 1b. By doing so, the high density strand layer 1a and the low density strand layer 1b can be mixed and laminated together.
  • the first strand generation step two types of strands, that is, a strand having a density in a general general range and a strand having a density higher than that are prepared in advance. And about the strand aggregate
  • the strand aggregate used as the high-density strand layer 1a the strand 5 may have a density higher than the normal range by compression or the like.
  • the strand aggregates that become the high-density strand layer 1a are made different from the strand 5 of the strand aggregate that becomes the high-density strand layer 1a and the strand 5 of the strand aggregate that becomes the low-density layer strand layer 1b.
  • a tree species having a higher density than the strand 5 of the strand assembly that becomes the low-density layer strand layer 1b may be used.
  • the press pressure related to the hot-pressing process is The pressure is, for example, 2 to 4 N / mm 2 as in the first embodiment, but the pressing time is, for example, 10 to 30 minutes. In the second embodiment as well, the pressing time varies depending on the thickness of the strand board B (finished product), and may be completed in less than 10 minutes, or may be required in 30 minutes or more. Moreover, you may perform the preheating process by a heating apparatus before the hot press process by a hot press apparatus.
  • the strand 5 produced in the strand production step preferably has a density of 300 to 1100 kg / m 3 and a moisture content of 2 to 8%. can do.
  • FIG. 4 shows a second example of the strand board B.
  • the strand board B is composed of first to fifth five strand layers 1, 1,..., As in the first example.
  • Each of the strand layers 1, 1,... Is laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1.
  • Two of the five strand layers 1, 1,... Are high-density strand layers 1a, and the other three layers are low-density strand layers 1b having a lower density than the high-density strand layers 1a.
  • the two high-density strand layers 1a and 1a have the same density, for example, 1100 kg / m 3 (average value), and this density is higher than the high-density strand layer 1a of the first example.
  • the three low-density strand layers 1b, 1b,... Have the same density, and this density is lower than the low-density strand layer 1b of the first example (the product density of the strand board B is lower than that of the first example). For).
  • the first strand layer 1 located at the front end of the strand board B and the fifth strand layer 1 located at the back end are the high-density strand layer 1a.
  • the second to fourth strand layers 1, 1,... Located in the remaining intermediate portion in the thickness direction are low-density strand layers 1b.
  • the thicknesses of the five strand layers 1, 1,... are the same, and the thickness of each strand layer 1 occupies, for example, 20% of the total thickness of the strand board B. Accordingly, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 40%. Further, the five strand layers 1, 1,... Are laminated so that the density distribution by the strand layers 1, 1,... Is symmetrical with respect to the center position in the thickness direction of the strand board B. .
  • the total thickness of the strand board B is 9 mm, for example.
  • FIG. 5 shows a third example of the strand board B.
  • the strand board B is composed of first to seventh seven strand layers 1, 1,.
  • the strand layers 1, 1,... Are laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1.
  • Two of the seven strand layers 1, 1,... Are high-density strand layers 1a.
  • the other five layers are low density strand layers 1b having a density lower than that of the high density strand layers 1a.
  • the two high-density strand layers 1a and 1a have the same density, for example, 1000 kg / m 3 (average value), and this density is the same as the high-density strand layer 1a of the first example.
  • the five low-density strand layers 1b, 1b,... Have the same density, and this density is lower than the low-density strand layer 1b of the first example (the product density of the strand board B is lower than that of the first example). For).
  • the first strand layer 1 located at the front side end of the strand board B and the seventh strand layer 1 located at the back side end constitute the high-density strand layer 1a.
  • the second to sixth strand layers 1, 1,... Located in the remaining intermediate portion in the thickness direction are all low-density strand layers 1b.
  • the seven strand layers 1, 1,... Have different thicknesses and are divided into two.
  • the thickness of each of the first and seventh strand layers 1 and 1 (high-density strand layer 1a) is, for example, 15% with respect to the entire thickness of the strand board B, and the second, third, fifth and sixth
  • Each thickness of the strand layers 1, 1,... (Low density strand layer 1b) occupies, for example, 15%, and further, the thickness of the fourth strand layer 1 (low density strand layer 1b) occupies, for example, 10%.
  • the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 30%.
  • the seven strand layers 1, 1,... Are laminated so that the density distribution of the strand layers 1, 1,... Is plane-symmetric with respect to the center position in the thickness direction of the strand board B. .
  • the total thickness of the strand board B is 12 mm, for example.
  • FIG. 6 shows a fourth example of the strand board B.
  • the strand board B includes first to third three strand layers 1, 1,.
  • the strand layers 1, 1,... Are laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1.
  • One of the three strand layers 1, 1,... Is a high-density strand layer 1a.
  • the other two layers are a low density strand layer 1b having a lower density than the high density strand layer 1a.
  • the density of one high-density strand layer 1a is, for example, 800 kg / m 3 (average value), which is lower than the high-density strand layer 1a of the second example.
  • the two strand layers 1b and 1b, which are low density layers have the same density, and this density is the same as the low density strand layer 1b of the first example.
  • the second strand layer 1 located at the center portion (intermediate portion) in the thickness direction of the strand board B is the high-density strand layer 1a, and the first and third strands located at the front and back side end portions.
  • Layers 1 and 1 are low density strand layers 1b.
  • the three strand layers 1, 1,... Have different thicknesses and are divided into two.
  • the thickness of each of the first and third strand layers 1 and 1 (low density strand layer 1b) is, for example, 20% of the total thickness of the strand board B, and the second strand layer 1 (high density strand layer 1a). ) Occupies 60%, for example. Accordingly, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 60%.
  • the three strand layers 1, 1,... Are laminated so that the density distribution of the strand layers 1, 1,... Is symmetrical with respect to the center position in the thickness direction of the strand board B. .
  • the total thickness of the strand board B is 18 mm, for example.
  • FIG. 7 shows a fifth example of the strand board B.
  • FIG. This strand board B is composed of first to third three strand layers 1, 1,... As in the fourth example.
  • the strand layers 1, 1,... are laminated and integrated so that the fibers of the strands 5 extend in parallel directions between the adjacent strand layers 1. . That is, the fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end of FIG. 7 positioned at the front side end of the strand board B and the third strand layer 1 at the lower end of FIG. is there. Further, the fiber direction of the strand 5 in the second strand layer 1 located at the center portion in the thickness direction of the strand board B is also the same as the fiber direction of the strands 5 and 5 of the first and third strand layers 1 and 1.
  • two of the three strand layers 1, 1,... are high-density strand layers 1a, and the other one is a low-density strand layer 1b.
  • the two high-density strand layers 1a and 1a have a density of, for example, 800 kg / m 3 (average value), and this density is the same as the high-density strand layer 1a of the fourth example.
  • the density of one low-density strand layer 1b is lower than that of the first example low-density strand layer 1b (because the product density of the strand board B is lower than that of the first example).
  • the first and third strand layers 1, 1 located at the front and back end portions of the strand board B are high-density strand layers 1 a, and only the second strand layer 1 located at the center in the thickness direction. Is a low density strand layer 1b.
  • the three strand layers 1, 1,... Have different thicknesses and are divided into two.
  • the thickness of each of the first and third strand layers 1 and 1 (high-density strand layer 1a) is, for example, 40% of the total thickness of the strand board B, and the second strand layer 1 (low-density strand layer 1b). ) Occupies, for example, 20%.
  • the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 80%.
  • the three strand layers 1, 1,... Are laminated so that the density distribution by the strand layers 1, 1,. .
  • the total thickness of the strand board B is 15 mm, for example.
  • FIG. 8 shows a sixth example of the strand board B.
  • the strand board B is composed of first to fifth five strand layers 1, 1,..., As in the first example.
  • Each of the strand layers 1, 1,... Is laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1.
  • Three of the five strand layers 1, 1,... are high-density strand layers 1a.
  • the other two layers are a low density strand layer 1b having a lower density than the high density strand layer 1a.
  • the three high density strand layers 1a, 1a,... Have the same density, for example, 1000 kg / m 3 (average value), and this density is the same as the high density strand layer 1a of the first example.
  • the two low-density strand layers 1b and 1b have the same density, and this density is the same as the low-density strand layer 1b of the first example.
  • the second to fourth strand layers 1, 1,... Located in the middle portion of the strand board B in the thickness direction are high-density strand layers 1a.
  • the first strand layer 1 located at the remaining front end and the fifth strand layer 1 located at the rear end constitute a low density strand layer 1b.
  • the five strand layers 1, 1,... Have different thicknesses and are divided into three.
  • the thickness of each of the first and fifth strand layers 1 and 1 (low density strand layer 1b) is, for example, 30% with respect to the total thickness of the strand board B, and the second and fourth strand layers 1 and 1 (
  • Each thickness of the high-density strand layer 1a) occupies, for example, 15%, and further, the thickness of the third strand layer 1 (high-density strand layer 1a) occupies, for example, 10%.
  • the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 60%.
  • the five strand layers 1, 1,... Are laminated so that the density distribution by the strand layers 1, 1,... Is symmetrical with respect to the center position in the thickness direction of the strand board B. .
  • the total thickness of the strand board B is 28 mm, for example.
  • FIG. 1 A specific configuration of the first to sixth examples is shown in FIG. 1
  • the strand board B is composed of a plurality of strand layers 1, 1,..., And a part (1 to 3 layers) of the strand layers 1 is more than the other strand layers 1. Is a high-density strand layer 1a having a high density. Therefore, the high-strength strand layer 1a can realize the high strength and high water resistance of the strand board B, and the strand board B having high strength and high water resistance can be obtained.
  • the density of the strand layer 1 in the strand board B is increased to form the high-density strand layer 1a
  • only the strands 5 of the high-density strand layer 1a may be increased in density. It is not necessary to increase the density of the strands 5. Accordingly, the press time by the press machine is shortened, the press pressure is lowered, the productivity can be improved, and the puncture at the time of molding can be prevented.
  • a layer to be the high-density strand layer 1a can be selected from the layers 1, 1,.
  • various variations can be obtained as the characteristics of the strand board B by changing the position of the high-density strand layer 1a, and effects specific to each example can be achieved.
  • the second and fourth strands located in the portion excluding the front and back end portions and the thickness direction central portion of the strand board B.
  • the layers 1, 1 are high-density strand layers 1a, and the first, third, and fifth strand layers 1, 1,... Located at the remaining front and back end portions and the thickness direction central portion are low-density strands with low density.
  • Layer 1b is high-density strand layers 1a, and the first, third, and fifth strand layers 1, 1,... Located at the remaining front and back end portions and the thickness direction central portion are low-density strands with low density.
  • the extraction resistance (force) with respect to the nail as a fixing tool struck by the strand board B is increased by the high density strand layer 1a.
  • the strand layers 1 and 1 located at the front and back end portions of the strand board B are the high-density strand layers 1 a and the strand layers located at the intermediate portion. 1, 1,... Are low density strand layers 1b.
  • the high-strength strand layer 1a on the front and back portions can increase the bending strength of the strand board B and improve the water resistance of the front and back portions.
  • the strand layer 1 located in the front and back intermediate part of the strand board B is made into the high density strand layer 1a, and the strand layers 1 and 1 located in other parts are the low density strand layer 1b. It is.
  • the density of the intermediate portion is increased by the high-density strand layer 1a, and the density distribution seen from the entire thickness direction of the strand board B can be made uniform.
  • the high density strand layer 1a is arrange
  • the strand layer 1 located at the front and back center portions of the strand board B is the high-density strand layer 1 a
  • the first and third strand layers located at the front and back side ends of the strand board B 1, 1 is the low-density strand layer 1b.
  • the fibers of the strands 5, 5,... In each strand layer 1 extend in the same direction, and the strands 5 of the adjacent strand layers 1 The fibers extend in directions perpendicular to each other.
  • the fibers of the strand 5 extend in the same direction over all the strand layers 1, 1,.
  • high strength can be realized, and the difference in strength due to the difference in the fiber direction becomes more remarkable as the number of strand layers 1 is increased.
  • the same performance is obtained on both the front side and the back side of the strand board B. Can be obtained regardless of the front and back of the strand board B.
  • the strand board B is a laminate of odd-numbered strand layers 1, 1,..., The same performance can be obtained on both the front side and the back side of the strand board B.
  • the present invention is not limited to the first and second embodiments.
  • the thicknesses w1 to w3 of the plurality of strand layers 1, 1,... are all the same.
  • the present invention is not limited to this, and the thicknesses w1 to w3 of each layer 1 are arbitrarily set. Can do.
  • the plurality of strand layers 1, 1,... May be configured so that the thickness gradually increases from the inner layer in the thickness direction (lamination direction) toward the outer layer. That is, in FIG. 1, the thicknesses of the plurality of strand layers 1, 1,... May have a relationship of w1> w2> w3.
  • the external environment in the strand board B can be increased by making the thickness of the outer (front and back) strand layer 1 that is susceptible to load and impact and also susceptible to humidity and the like to be thicker than the other strand layers 1. The performance against the influence from can be improved.
  • the thicknesses of the plurality of strand layers 1, 1,... May be different from each other.
  • the thickness w1 of the two strand layers 1, 1 on the front surface and the back surface may be different from the thickness w2, w3 of the three intermediate strand layers 1, 1,.
  • the thicknesses of all five strand layers 1, 1,... May be different from each other.
  • the fiber directions of the strands 5, 5,... are orthogonal to the fiber directions of the strands 5, 5,.
  • the fiber directions may be the same.
  • the density and thickness of the strands 5 (wood materials) constituting each strand layer 1 of the strand board B may be different between the strand layers 1, 1,.
  • the relative density of the strands 5 of each strand assembly is the outer strand layer in the thickness direction.
  • the layers may be stacked so as to gradually increase from 1 toward the inner strand layer 1.
  • the outer strand layer 1 to which the press machine pressure is directly applied has a higher relative density than the inner strand layer 1.
  • the relative density of the strands 5 of the inner strand layer 1 is set higher than that of the outer strand layer 1 in advance, so that the strand board B is laminated in the stacking direction after the pressing process.
  • the density distribution can be made uniform. In this case, the tree species of the strands 5 constituting each strand layer 1 may be different from each other or the same.
  • the tree type, thickness, density, and the like of the strands 5 of each strand layer 1 can be appropriately selected according to necessary characteristics and costs.
  • the strand assembly is formed so that at least one of the plurality of strand layers 1, 1,. May be stacked.
  • the strand layer 1 is a layer composed of strands 5 having a relatively higher density than the other strand layers 1.
  • the strand board B has the odd-numbered strand layers 1
  • the odd-numbered strand layers 1 as viewed from the front side or the back side are laminated so as to be composed of the high-density strands 5. May be.
  • the specific strand layer 1 at least one layer of the plurality of strand layers 1, 1,. , 5,...
  • the strand board B shall be provided with the odd number of strand layers 1, 1, ..., the lamination
  • the odd number is preferable in that the same performance can be obtained on both the front surface side and the back surface side of the strand board B.
  • the fibers of the strands 6 in each strand layer 1 are the same as each other, and the fiber directions of the strands 5 and 5 of the adjacent strand layers 1 are orthogonal or parallel to each other.
  • the fiber direction of the strand 5 of each strand layer 1 can be freely selected.
  • the strand board B in which the aggregates of the strands 5 are laminated in a board shape has been described.
  • the present invention is not limited to such a strand board B.
  • a plurality of strand layers having a rectangular cross-section (square material shape) with no significant difference in thickness and width may be laminated.
  • the strand material wood laminate
  • the strand material is a laminate of a plurality of strand layers. It can be a joist or a pillar.
  • first and second embodiments are examples of the strand board B that is integrated in a state where a plurality of strand layers 1, 1,. is there.
  • the present invention can be applied to, for example, plywood or LVL (Laminated Veneer Lumber).
  • a single plate may be used instead of the aggregate of strands 5. That is, in the case of plywood or LVL, each wood material layer is composed of at least one single plate.
  • the wood laminate is plywood or LVL
  • a general plywood or LVL manufacturing method can be adopted as the manufacturing method. Specifically, a single board is generated by cutting raw wood such as logs and thinned wood with a cutting machine. Next, in the state where a plurality of single plates have an adhesive interposed between the single plates, the fiber directions of adjacent single plates in LVL are the same direction, and in the case of plywood, the fiber directions of adjacent single plates are orthogonal to each other. Each is laminated. Thereafter, the adhesive may be cured by forming a laminate of single plates by cold pressing or hot pressing.
  • the density and thickness of each single plate are preliminarily formed. Etc. may be set.
  • the wood material layer is a combination of a high-density wood material layer and a low-density wood material layer as in the second embodiment
  • a part of the wood material is preliminarily formed, for example, before being formed in the press molding process.
  • the density of the wood material constituting each wood material layer may be made higher than that of other wood material layers depending on the type of tree.
  • Example 1 A length of 150 to 200 mm along the fiber direction, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm and a density of 500 to 600 kg / m 3 of a large number of cypress strands are laminated to form 5 A laminated mat having a thickness of 37 mm composed of multiple strand layers was formed. Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 4 N / mm 2 for 10 minutes to obtain a strand board having a density of 818 kg / m 3 and a thickness of 12.4 mm. This is Example 1.
  • Example 1 The appearance photograph of Example 1 is shown in FIG. In FIG. 10, B is a strand board and 1 is a strand layer. Moreover, the result of having done the bending test, the dimensional change test, and the water absorption test about this Example 1 is shown in FIG. Furthermore, the result of measuring the density distribution in the thickness direction (stacking direction) of the strand board using a density distribution measuring apparatus (“DENSE-LAB® X” manufactured by ELECTRONIC® WOOD® SYSTEMSGMBH) is shown in FIG.
  • a density distribution measuring apparatus (“DENSE-LAB® X” manufactured by ELECTRONIC® WOOD® SYSTEMSGMBH)
  • Example 2 An assembly of a large number of strands made of bay pine having a length along the fiber direction of 150 to 200 mm, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm, and a density of 450 to 550 kg / m 3 is laminated. A laminated mat having a thickness of 36 mm composed of a plurality of strand layers was formed. Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 4 N / mm 2 for 10 minutes to obtain a strand board having a density of 832 kg / m 3 and a thickness of 12.2 mm. The results of a bending test, a dimensional change test, and a water absorption test for Example 2 are shown in FIG.
  • Comparative Example 1 A length of 150 to 200 mm along the fiber direction, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm and a density of 400 to 500 kg / m 3 of a large number of cypress strands are laminated to form 5 A laminated mat having a thickness of 42 mm composed of a single strand layer was formed. Thereafter, hot pressing was performed for 10 minutes at a pressing temperature of 140 ° C. and a pressing pressure of 8 N / mm 2 to obtain a strand board having a density of 779 kg / m 3 and a thickness of 12.7 mm. The results of a bending test, a dimensional change test, and a water absorption test for Comparative Example 1 are shown in FIG. Furthermore, the result of having measured the density distribution of the thickness direction (lamination direction) of a strand board using the density distribution measuring apparatus (DENSE-LAB X, ELECTRONIC WOOD SYSTEMSGMBH company) is shown in FIG.
  • Comparative Example 2 An aggregate of a large number of strands made of bay pine having a length along the fiber direction of 150 to 200 mm, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm, and a density of 350 to 450 kg / m 3 is laminated to 5 A laminated mat having a thickness of 35 mm composed of a single strand layer was formed. Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 8 N / mm 2 for 10 minutes to obtain a strand board having a density of 812 kg / m 3 and a thickness of 12.4 mm. The results of a bending test, a dimensional change test, and a water absorption test for Comparative Example 2 are shown in FIG.
  • Example 1 has a higher density and higher bending strength, MOR (Modulus of Rupture) and MOE (Modulus of Elasticity) than Comparative Example 1.
  • the dimensional change rate and the water absorption rate are the same values in Example 1 and Comparative Example 1.
  • Example 2 has a higher density, bending strength and MOR are substantially the same, and MOE is higher than that of Comparative Example 2.
  • the dimensional change rate and the water absorption rate are the same values in Example 2 and Comparative Example 2.
  • the density distribution in the stacking direction of the plurality of strand layers in Example 1 is substantially constant as compared with Comparative Example 1.
  • the density distribution is substantially constant, for example, as shown in FIGS. 12 and 13, when there is a change in the measurement result of the density distribution, there is little change in the intermediate value indicated by the broken line in each figure. It is assumed that the intermediate value is substantially constant. For example, when the broken line shown in FIG. 12 (Example 1) is compared with the broken line shown in FIG. 13 (Comparative Example 1), the intermediate value of the density distribution shown in FIG. It is a constant value.
  • the density distribution is substantially constant, there is no uneven density distribution, and the water resistance and strength (shear strength, etc.) of the entire strand board are improved. Specifically, the portion with low density is inferior in water resistance and strength as compared with the portion with high density. Therefore, if the density distribution is uneven, the performance of the entire strand board is regulated by the water resistance and strength of the portion where the density is low. On the other hand, when the density distribution is substantially constant, a portion that becomes a bottleneck of such performance can be eliminated.
  • the above bending test was performed according to IICL_Floor_Performance TB001 Ver.2.
  • the dimensional change test and the water absorption test were conducted in accordance with the repeated boiling test of Japanese agricultural and forestry standards for plywood.
  • Example 1 An aggregate of a large number of strands made of aspen having a thickness of 0.8 mm and a density of 300 to 600 kg / m 3 was laminated to form a laminated mat having a thickness of 53 mm consisting of five strand layers.
  • the strands of the second to fourth strand layers located at the intermediate portion in the stacking direction are generally ordinary strands.
  • the one having a density (average value 393 kg / m 3 ) was used.
  • the density average value 557 kg / m ⁇ 3 >) whose density is higher than usual is used.
  • Example 1 a strand board, which was designated as Example 1.
  • the target thickness arrival time at the time of pressing was 24 seconds.
  • Example 2 In the same manner as in Example 1, a laminated mat having a thickness of 52 mm composed of five strand layers was formed. Among the five strand layers, the strands of the first and fifth strand layers located at both ends in the stacking direction were higher in density than Example 1 (average value 805 kg / m 3 ). Thereafter, hot pressing was performed under the same conditions as in Example 1 to obtain a strand board, which was designated as Example 2. The target thickness arrival time at the time of pressing was 12 seconds. Others are the same as Example 1.
  • Example 1 Comparative Example 1
  • a laminated mat having a thickness of 62 mm composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 393 kg / m 3 ). Then, the hot press was performed on the conditions similar to Example 1, the strand board was obtained, and it was set as Example 1. The target thickness arrival time during pressing was 33 seconds. Others are the same as Example 1.
  • Test A Each of Examples 1 and 2 and Comparative Example 1 was subjected to a normal bending test (the bending test span was 225 mm). The results are shown in FIG. 14 together with other physical properties.
  • the density distribution in the thickness direction (stacking direction) of the strand board was measured using the above-described density distribution measuring apparatus (“DENSE-LAB® X” manufactured by ELECTRONIC WOOD WOOD SYSTEMSGMBH). The result is shown in FIG.
  • Example 1 and Example 2 are made to be high-density strand layers.
  • the thickness (bulk height) of the laminated mat before pressing becomes small, and the pressing time (target thickness reaching time) until the laminated mat is easily crushed and reaches the target value also during pressing is shortened.
  • MOR and MOE are the same as those in Comparative Example 1 in both Example 1 and Example 2.
  • Example 3 An assembly of a large number of strands made of aspen having a thickness of 0.8 mm and a density of 300 to 600 kg / m 3 was laminated to form a laminated mat having a thickness of 70 mm composed of five strand layers.
  • the first and third strands excluding the second and fourth strand layers located in the intermediate portion in the stacking direction.
  • the strands of the fifth strand layer those having a general density (average value of 393 kg / m 3 ) were used.
  • the density average value of 933 kg / m ⁇ 3 >) whose density is higher than usual is used.
  • Example 2 (Comparative Example 2) In the same manner as in Example 3, a laminated mat having a thickness of 78 mm composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 393 kg / m 3 ). Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 8 N / mm 2 for 10 minutes to obtain a strand board having a density of 848 kg / m 3 and a thickness of 12.6 mm. Others are the same as Example 3.
  • Example 3 in which the second and fourth strand layers located in the intermediate portion in the stacking direction of the five strand layers are the high-density strand layers, and all the five layers are low.
  • the bending strength of Example 3 and the peel strength after the boiling test were the same as or higher than those of Comparative Example 2 and were not lower than those of Comparative Example 2.
  • Example 4 An aggregate of a large number of strands made of aspen having a thickness of 0.8 mm and a density of 300 to 600 kg / m 3 was laminated to form a laminated mat having a thickness of 130 mm consisting of five strand layers.
  • the first and fifth strand layers except for the second to fourth strand layers located in the intermediate portion in the stacking direction are used.
  • the strand of the strand layer one having a general density (average value 413 kg / m 3 ) was used.
  • the strands of the second to fourth strand layers used have a higher density than normal (average value 1100 kg / m 3 ).
  • Example 3 (Comparative Example 3) In the same manner as in Example 4, a laminated mat composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 413 kg / m 3 ). Thereafter, a hot press for 60 minutes was performed at a press temperature of 140 ° C. and a press pressure of 8 N / mm 2 to obtain a strand board having a predetermined density and thickness (see FIG. 18). Other processes are the same as those in the fourth embodiment.
  • Comparative Example 4 In the same manner as in Example 4, a laminated mat composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 413 kg / m 3 ). Thereafter, hot pressing for 30 minutes at a pressing temperature of 160 ° C. and a pressing pressure of 8 N / mm 2 was performed to obtain a strand board having a predetermined density and thickness. In Comparative Example 4, the press temperature is higher than that of Comparative Example 3 in order to avoid poor curing of the adhesive in winter. Comparative Example 4 is of a small size, and the pressing time is shorter than that of Example 4 or Comparative Example 3. Other processes are the same as those in the fourth embodiment.
  • Example 4 and Comparative Example 4 a nail pull-out test was performed on Example 4 and Comparative Example 4.
  • the tip hole formed in each sample of Example 4 and Comparative Example 4 has an inner diameter of 2 mm and a depth of 25 mm.
  • Test A the result of measuring the density distribution in the thickness direction (stacking direction) of the strand board using a density distribution measuring device is shown in FIG.
  • Example 4 in which the second to fourth strand layers located in the middle portion in the stacking direction of the five strand layers are high-density strand layers, all the five layers are reduced.
  • the bending strength of Example 4 was almost the same as that of Comparative Example 3, and the peel strength after the boiling test of Example 4 was higher than that of Comparative Example 3.
  • a strand board having the same performance as that of Comparative Example 3 can be formed by making the second to fourth strand layers of the five strand layers into high-density strand layers.
  • the nail pulling resistance (force) is increased if the second to fourth strand layers located in the middle in the thickness direction of the five strand layers are high-density strand layers. It can be seen that the same performance improvement can be achieved.
  • the present invention is suitable for use as a flooring material for containers, ships, vehicles and the like.
  • it is extremely useful as a new building material suitable for use as a flooring material and load bearing surface material for buildings such as houses, and has high industrial applicability.

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  • Engineering & Computer Science (AREA)
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  • Laminated Bodies (AREA)

Abstract

Through the present invention, the strength and water-resistant performance of a strand board are increased. The production yield of the strand board is also prevented from decreasing while a certain degree of high strength and high water-resistant performance are realized therein, and it becomes possible to change a variation in characteristics of the strand board. In a strand board B, five strand layers 1 formed by numerous strands 5 are integrated in a layered state, and the density distribution in the layering direction of the strand layers 1 is made essentially constant. Three of the five strand layers 1 of the strand board B are configured as high-density strand layers 1a having higher density than the other strand layers 1, and the other strand layers 1 are configured as low-density strand layers 1b.

Description

木質積層材及びその製造方法WOOD LAMINATE AND MANUFACTURING METHOD THEREOF
　本発明は、木質材で構成された複数の木質材層が積層された状態で一体化された木質積層材及びその製造方法に関する。 The present invention relates to a wood laminate material that is integrated in a state where a plurality of wood material layers made of wood material are laminated, and a method for manufacturing the same.
　今日、アピトンやクルインといった広葉樹からなる南洋材が少なくなってきており、良質な単板を安価で入手することが困難となっている。そのため、それらの南洋材を用いた合板の品質低下が大きな問題となっている。合板の代替材料としてＯＳＢ（Oriented Strand Board）等の木質繊維板が用いられつつあるが、一般的な密度のＯＳＢでは十分な強度を得ることができない。 Today, the number of southern seawood made of hardwood such as Apiton and Kruin is decreasing, making it difficult to obtain good quality veneers at low cost. Therefore, the deterioration of the quality of the plywood using those southern materials is a big problem. Wood fiber boards such as OSB (Oriented Strand Board) are being used as substitute materials for plywood, but sufficient strength cannot be obtained with a general density OSB.
　従来、例えば特許文献１には、最大で７００ｋｇ／ｍ３の密度を有し、長さが少なくとも７ｍあり、主負荷方向における曲げ弾性係数として少なくとも７０００Ｎ／ｍｍ２である大型のＯＳＢプレートが開示されている。 Conventionally, for example, Patent Document 1 discloses a large OSB plate having a maximum density of 700 kg / m 3 , a length of at least 7 m, and a bending elastic modulus in the main load direction of at least 7000 N / mm 2. ing.
　また、特許文献２には、木質材料片を配向させて積層し、加圧・加熱して成形されたストランド材を根太や土台等に用いる技術が開示されている。 Patent Document 2 discloses a technique in which a strand material formed by orienting and stacking wood material pieces and pressurizing and heating is used as a joist or foundation.
特許第４３０７９９２号公報Japanese Patent No. 4307922 特許第４２２７８６４号公報Japanese Patent No. 4227864
　しかし、特許文献１のＯＳＢプレートは、ボードを成形する際のプレス圧力として、一般的な圧力よりも高い圧力を必要とするため、特殊なプレス機を用いなければ成形することができない。 However, since the OSB plate of Patent Document 1 requires a pressure higher than a general pressure as a press pressure when forming a board, it cannot be formed unless a special press machine is used.
　そして、本発明者によると、上記のような特殊なプレス機を用いて一般的な圧力よりも高いプレス圧力でボードを成形した場合、ボードの厚さ方向の密度分布が不均一となることが判明した。密度分布が不均一であると、密度の低い部分が強度的に弱くなる傾向がある。また、密度が低い部分は高い部分と比較して、吸水性が高くなって耐水性能が劣る。このように密度分布の不均一が生じる結果、強度及び耐水性能が低密度部分により律則され、十分な強度や耐水性能が得られないという問題が生じる。 And, according to the present inventors, when a board is molded at a press pressure higher than a general pressure using a special press as described above, the density distribution in the thickness direction of the board may be non-uniform. found. If the density distribution is not uniform, the low density portion tends to be weak in strength. In addition, the portion having a low density has a higher water absorption and the water resistance is inferior than the portion having a high density. As a result of the uneven density distribution, the strength and water resistance are regulated by the low density portion, and there is a problem that sufficient strength and water resistance cannot be obtained.
　他方、ストランド等の木質材が積層された木質積層材において、その全ての木質材層を高密度とすれば、高い強度及び耐水性能を実現することができる。 On the other hand, in a wooden laminated material in which wooden materials such as strands are laminated, if all the wooden material layers have a high density, high strength and water resistance can be realized.
　しかし、その場合、積層された複数の木質材層の全体を高密度化するのに多大な手間を要し、生産性が低下するのは避けられない。しかも、木質材層の全てが高密度化されているので、木質積層材として得られる特性は一定となり、種々の用途に適用しようとするために特性のバリエーションを変更することは困難となる。 However, in that case, a great deal of labor is required to increase the density of the entire laminated wood material layers, and it is inevitable that the productivity is lowered. In addition, since all the wood material layers are densified, the characteristics obtained as a wood laminate are constant, and it is difficult to change the variations of the characteristics in order to apply to various uses.
　本発明の目的は、複数の木質材が積層された木質積層材において、その積層方向の密度分布を調整することにより、高強度かつ耐水性能の高い木質積層材が得られるようにすることにある。また、木質積層材にある程度の高強度及び高耐水性能を実現しながら、その木質積層材の製造するときの生産性が低下するのを防ぎ、かつ木質積層材の特性のバリエーションを変更できるようにすることにある。 An object of the present invention is to obtain a wood laminate material having high strength and high water resistance by adjusting the density distribution in the lamination direction in a wood laminate material in which a plurality of wood materials are laminated. . In addition, while realizing a certain level of high strength and high water resistance to the wood laminate, it is possible to prevent a decrease in productivity when manufacturing the wood laminate, and to change variations in the properties of the wood laminate. There is to do.
　上記の目的を達成するために、本発明では、木質積層材における積層方向の密度分布を実質的に一定として、木質積層材の高強度化及び高耐水性能化を実現するようにした。 In order to achieve the above object, in the present invention, the density distribution in the stacking direction of the wood laminate is made substantially constant, and the strength and water resistance of the wood laminate are increased.
　具体的には、本発明では、各々、集合状態の複数の切削片からなる木質材又は単板からなる木質材で構成された複数の木質材層が積層された状態で一体化された木質積層材として、上記木質材層の積層方向の密度分布が実質的に一定であることを特徴とする。 Specifically, in the present invention, each of the wood laminates integrated in a state where a plurality of wood material layers composed of a wood material composed of a plurality of cutting pieces in a collective state or a wood material composed of a single plate are laminated. As a material, the density distribution in the stacking direction of the wood material layer is substantially constant.
　この構成によると、木質積層材はその積層方向の密度分布が実質的に一定となっている。前述のとおり、積層方向について密度分布の不均一な部分がある場合、低密度部分によりその強度及び耐水性能が律則されるが、この発明に係る木質積層材では、そのような問題は生じない。従って、高強度かつ高い耐水性能を有する木質積層材を実現することができる。 According to this configuration, the density distribution in the stacking direction of the wood laminate is substantially constant. As described above, when there is a non-uniform portion of the density distribution in the stacking direction, the strength and water resistance are regulated by the low-density portion, but such a problem does not occur in the wood laminate according to the present invention. . Therefore, a wood laminate having high strength and high water resistance can be realized.
　上記の構成において、上記木質材の密度を３００ｋｇ／ｍ３以上かつ１１００ｋｇ／ｍ３以下としてもよく、さらには３００Ｋｇ／ｍ３以上かつ８００Ｋｇ／ｍ３以下とするのが好ましい。 In the above configuration, the wood material density may be less 300 kg / m 3 or more and 1100 kg / m 3 of, more preferably set to 300 Kg / m 3 or more and 800 Kg / m 3 or less.
　このように、木質材の密度を３００ｋｇ／ｍ３以上としているため、同密度・同強度の木質積層材を形成するために必要な積層体の厚さ（積層体が一体化される前の積層厚さ）を薄くすることができる。このように、積層体の厚さを薄くできるので、一体化に係る工程（例えば積層工程及び成形工程）の作業性を向上させることができる。また、同密度・同強度の木質積層材を生成するために必要な一体化のためのプレス圧を低くすることができる。 As described above, since the density of the wooden material is set to 300 kg / m 3 or more, the thickness of the laminated body necessary for forming the wooden laminated material having the same density and the same strength (the laminated body before the laminated body is integrated). (Thickness) can be reduced. Thus, since the thickness of a laminated body can be made thin, the workability | operativity of the process (for example, a lamination process and a formation process) concerning integration can be improved. Moreover, the press pressure for integration required in order to produce | generate the wood laminated material of the same density and the same intensity | strength can be made low.
　上記複数の木質材層の厚さは、積層方向の内側から外側に向かって次第に厚さが増していてもよい。 The thickness of the plurality of wood material layers may gradually increase from the inner side to the outer side in the stacking direction.
　こうすれば、荷重や衝撃、湿度等の影響を受け易い外側の層の厚さが内側に比べて厚くなることにより、木質積層材における外部環境に対する性能を高めることができる。 In this case, the thickness of the outer layer that is easily affected by the load, impact, humidity, and the like becomes thicker than that of the inner layer, so that the performance of the wooden laminated material against the external environment can be improved.
　他方、本発明では、積層された全ての木質材層を高密度にするのではなく、一部の木質材層のみを高密度化して、その高密度化された木質材層によって木質積層材の高強度や高耐水性能等を実現するようにした。 On the other hand, in the present invention, not all the laminated wood material layers are densified, but only a part of the wood material layers is densified, and the densified wood material layer is used to increase the density of the wood laminates. Realized high strength and high water resistance.
　具体的には、各々、集合状態の複数の切削片からなる木質材又は単板からなる木質材で構成された複数の木質材層が積層された状態で一体化された木質積層材として、上記複数の木質材層は、他の木質材層よりも密度の高い少なくとも１層の高密度木質材層と、上記他の木質材層からなる低密度木質材層とを備えていることを特徴とする。この場合、「木質材層の密度」とは、木質材が切削片であれば、それらの集合体の密度を、また木質材が単板であれば、その単板自体の密度をそれぞれ指している。 Specifically, each of the above-described wood laminates integrated in a state where a plurality of wood material layers composed of a wood material consisting of a plurality of cutting pieces in a collective state or a wood material consisting of a single plate are laminated, The plurality of wood material layers includes at least one high-density wood material layer having a higher density than other wood material layers, and a low-density wood material layer composed of the other wood material layers. To do. In this case, the “density of the wood material layer” means the density of the aggregate if the wood material is a cut piece, and the density of the veneer itself if the wood material is a single plate. Yes.
　この構成により、複数の木質材層のうちの少なくとも１層が高密度木質材層とされ、他の層は低密度木質材層とされているので、その高密度木質材層によって木質積層材の高強度及び高耐水性能を実現することができる。 With this configuration, at least one of the plurality of wood material layers is a high-density wood material layer, and the other layers are low-density wood material layers. High strength and high water resistance can be realized.
　また、木質材層の密度を高くする場合、例えば高密度が必要な木質材層の木質材のみを高密度にすればよく、全ての木質材層の木質材を高密度にすることが不要となる。その分、プレス機によるプレス時間が短くなり、プレス圧力も低くなり、生産性を向上させることができるとともに、成形時のパンクを防止することもできる。 In addition, when increasing the density of the wood material layer, for example, it is only necessary to increase the density of the wood material layer that requires a high density, and it is not necessary to increase the density of the wood material layers of all the wood material layers. Become. Accordingly, the press time by the press machine is shortened, the press pressure is lowered, the productivity can be improved, and the puncture at the time of molding can be prevented.
　さらに、少なくとも１層の木質材層が高密度木質材層であることから、複数の木質材層の中から高密度木質材層とすべき層を必要に応じて選択することができ、高密度木質材層の位置の変更によって木質積層材の特性として種々のバリエーションが得られる。 Furthermore, since at least one wood material layer is a high-density wood material layer, a layer to be a high-density wood material layer can be selected as necessary from a plurality of wood material layers. By changing the position of the wood material layer, various variations can be obtained as the characteristics of the wood laminate.
　上記の構成において、木質材層の積層方向両端部に位置する木質材層が高密度木質材層とされていてもよい。 In the above configuration, the wood material layers located at both ends of the wood material layer in the stacking direction may be high-density wood material layers.
　こうすると、木質材層の積層方向両端部における木質材層が高密度木質材層とされて、他の部分よりも密度が高いので、木質積層材の曲げ強度を増大させることができるとともに、木質積層材の表裏部の耐水性能を向上させることができる。 In this way, the wood layer at both ends in the stacking direction of the wood layer is a high-density wood layer, and the density is higher than other parts, so that the bending strength of the wood laminate can be increased, and the wood The water resistance performance of the front and back portions of the laminated material can be improved.
　また、木質材層の積層方向中間部に位置する木質材層が高密度木質材層とされていてもよい。 Further, the wood material layer located in the middle part of the wood material layer in the stacking direction may be a high density wood material layer.
　この場合、上記とは逆に、木質材層の積層方向中間部における木質材層が高密度木質材層とされて、他の部分（木質材層の積層方向両端部）に位置する木質材層よりも密度が高くなっている。そのため、中間部の密度が高くなった分だけ木質積層材の積層方向の密度分布を均一にすることができる。また、木質積層材の積層方向中間部に高密度木質材層が配置され、表裏部は低密度であるので、成形時のパンクを有効に防止して生産性を向上させることができる。 In this case, contrary to the above, the wood material layer in the middle direction of the wood material layer is a high-density wood material layer, and the wood material layer located at the other part (both ends of the wood material layer in the lamination direction) The density is higher than. Therefore, the density distribution in the stacking direction of the wood laminate can be made uniform as much as the density of the intermediate portion is increased. Moreover, since a high-density wood material layer is arrange | positioned in the lamination direction intermediate part of a wood laminate, and the front and back parts are low density, the puncture at the time of shaping | molding can be prevented effectively and productivity can be improved.
　さらに、木質材層の積層方向両端部及び中央部を除いた部分に位置する木質材層が高密度木質材層とされていてもよい。 Furthermore, the wood material layer located in the portion excluding both ends and the center of the wood material layer in the stacking direction may be a high-density wood material layer.
　このことで、木質材層の積層方向両端部と中央部とを除いた部分に位置する木質材層が高密度木質材層とされ、積層方向両端部と中央部とに位置する木質材層は低密度となっている。そのため、木質積層材の表裏部の低密度層によって成形時のプレス圧力を低減できるとともに、木質積層材における釘引き抜き抵抗（力）を高密度木質材層によって増大させることができる。 With this, the wood material layer located in the portion excluding both ends and the center portion in the stacking direction of the wood material layer is a high density wood material layer, and the wood material layer located in the both ends and the center portion in the stacking direction is Low density. Therefore, the press pressure at the time of molding can be reduced by the low-density layers on the front and back sides of the wood laminate, and the nail pulling resistance (force) in the wood laminate can be increased by the high-density wood material layer.
　さらに、各木質材層における木質材の繊維が互いに同じ方向に延び、隣接する木質材層の木質材の繊維は、互いに交差する方向又は平行な方向に延びていてもよい。 Furthermore, the wood material fibers in each wood material layer may extend in the same direction, and the wood material fibers of adjacent wood material layers may extend in a direction intersecting or parallel to each other.
　ここで、「繊維が互いに同じ方向に延びる」及び「繊維が平行な方向に延びる」とは、木質材の繊維が互いに同一方向を向いているものに限定されず、繊維がある程度傾いているものを含む概念とする。繊維が所定の基準方向に対して例えば２０°程度傾いている木質材が含まれていてもよい。同様に「繊維が互いに交差する方向に延びる」とは、繊維が互いに直交方向を向いているものに限らず、基準方向に直交する直交方向に対して例えば２０°程度傾いている木質材が含まれていてもよい。 Here, “the fibers extend in the same direction” and “the fibers extend in the parallel direction” are not limited to those in which the fibers of the wood material are oriented in the same direction, and the fibers are inclined to some extent. A concept that includes A wood material in which the fibers are inclined by, for example, about 20 ° with respect to a predetermined reference direction may be included. Similarly, “extending in the direction in which the fibers cross each other” is not limited to those in which the fibers are oriented in the orthogonal direction to each other, but includes a wood material that is inclined, for example, by about 20 ° with respect to the orthogonal direction orthogonal to the reference direction. It may be.
　この構成によると、隣接する木質材層で木質材の繊維が互いに交差する方向に延びていれば、同繊維が木質材層の全体に亘って同じ方向に延びている場合と比較して、様々な方向からの力の作用に対し高い強度を実現することができる。特に、木質材層の積層数が増加するほど上記繊維方向の違いによる強度の差がより顕著になる。また、積層方向全体に亘って繊維の配向方向が同じ場合には、力の加わる方向によって強度が異なることが生じるが、そのようなことも生じない。 According to this structure, if the fibers of the wood material extend in the direction intersecting each other in the adjacent wood material layer, compared to the case where the fiber extends in the same direction over the entire wood material layer, there are various High strength can be achieved against the action of force from any direction. In particular, the difference in strength due to the difference in the fiber direction becomes more remarkable as the number of laminated wood material layers increases. In addition, when the fiber orientation direction is the same throughout the lamination direction, the strength may vary depending on the direction in which the force is applied, but this does not occur.
　一方、隣接する木質材層の木質材の繊維が互いに平行な方向に延びている場合、つまり積層方向全体に亘って木質材の繊維方向が同じ場合、特定の方向からの力の作用に対し高い強度を実現することができる。 On the other hand, when the fibers of the wood material adjacent to each other are extended in parallel to each other, that is, when the fiber direction of the wood material is the same throughout the lamination direction, it is high against the action of force from a specific direction. Strength can be realized.
　複数の木質材層のうちの表面層及び裏面層における木質材の繊維が互いに同じ方向に延びていてもよい。 The fibers of the wood material in the front surface layer and the back surface layer of the plurality of wood material layers may extend in the same direction.
　このことで、表面層側における耐荷重・耐衝撃等の性能と、裏面層側における同性能とを同じ程度に揃えることができる。すなわち、木質積層材の表裏で同様の性能を得ることができ、木質積層材の表裏を気にすることなく使用することができるメリットがある。 This makes it possible to equalize the performance such as load resistance and impact resistance on the surface layer side and the same performance on the back layer side. That is, there is an advantage that the same performance can be obtained on the front and back of the wood laminate, and the wood laminate can be used without worrying about the front and back of the wood laminate.
　木質材層の積層数は奇数としてもよい。こうすれば、木質積層材は奇数の木質材層が積層されたものとなり、上記と同様に、木質積層材の表面側及び裏面側の双方で同様の性能を得ることができる。 The number of wooden material layers may be an odd number. By doing so, the wooden laminated material is obtained by laminating an odd number of wooden material layers, and the same performance can be obtained on both the front surface side and the back surface side of the wooden laminated material as described above.
　複数の木質材層は、該複数の木質材層による密度の分布が積層方向の中央位置に対し面対称になるように積層されていてもよい。このことで、複数の木質材層による密度の分布がそれらの積層方向の中央位置に対し面対称であるので、木質積層材の表面側及び裏面側の双方で同様の性能を得ることができ、木質積層材の表裏を問わずに使用できる。 The plurality of wood material layers may be laminated so that the density distribution by the plurality of wood material layers is plane-symmetric with respect to the center position in the lamination direction. By this, since the density distribution by the plurality of wood material layers is plane-symmetric with respect to the center position in the lamination direction, the same performance can be obtained on both the front side and the back side of the wood laminate material, It can be used regardless of the front or back of the wood laminate.
　上記木質材は、切削片からなるストランドとしてもよい。そうすれば、高強度かつ高い耐水性能を有するストランド材、又は生産性が高くかつ特性のバリエーションが変更されたストランド材を実現することができる。 The wood material may be a strand made of a cut piece. By doing so, it is possible to realize a strand material having a high strength and a high water resistance, or a strand material having a high productivity and a variation in characteristics.
　木質積層材の製造方法として、切削片又は単板からなる複数の木質材を積み重ねることで、複数の木質材層を、少なくとも１つの木質材層の木質材が他の木質材層よりも相対的に密度の高い高密度の木質材で構成されるように形成する積層工程と、この積層工程で形成された複数の木質材層を一体的に成形する成形工程とを備えていることを特徴とする。 As a method of manufacturing a wood laminate, a plurality of wood materials made of cut pieces or single plates are stacked, so that a plurality of wood material layers are relative to each other, and at least one wood material layer is relative to other wood material layers. Characterized in that it comprises a laminating process for forming a high-density wood material having a high density and a molding process for integrally molding a plurality of wood material layers formed in this laminating process. To do.
　このように、木質材層として、他の木質材層よりも相対的に密度の高い高密度の木質材で構成された層を含ませることで、成形工程後の積層方向の密度分布を調整することが可能になり、所望の特性を有する木質積層材を得ることができる。例えば、高密度の木質材で構成された木質材層を挿入する場所を最適化することにより、木質積層材の積層方向の密度分布を実質的に一定にすることが可能になる。 Thus, the density distribution in the stacking direction after the molding process is adjusted by including a layer composed of a high-density wood material having a relatively higher density than the other wood material layers as the wood material layer. This makes it possible to obtain a wood laminate having desired characteristics. For example, the density distribution in the stacking direction of the wood laminate can be made substantially constant by optimizing the place where the wood material layer composed of the high-density wood is inserted.
　以上説明したように、本発明によれば、切削片又は単板からなる複数の木質材が積層された木質積層材の積層方向の密度分布を調整し、その積層方向の密度分布を実質的に一定にしたことにより、高強度かつ高い耐水性能を実現することができる。また、その積層方向の密度分布を異ならせ、複数の木質材層のうちの少なくとも１層を他の木質材層よりも密度の高い高密度木質材層としたことにより、高強度及び高耐水性能が必要な木質材層のみを高密度にして、生産性を向上させることができる。しかも、高密度木質材層となる層を変更して木質積層材の特性として種々のバリエーションが得られる。 As described above, according to the present invention, the density distribution in the stacking direction of the wood laminate in which a plurality of wood materials made of cutting pieces or single plates are laminated is adjusted, and the density distribution in the stacking direction is substantially reduced. By making it constant, high strength and high water resistance can be realized. In addition, the density distribution in the stacking direction is made different, and at least one of the plurality of wood material layers is a high density wood material layer having a higher density than other wood material layers, thereby providing high strength and high water resistance performance. Therefore, it is possible to improve the productivity by increasing the density of only the wood material layer that needs to be. Moreover, various variations can be obtained as the characteristics of the wood laminate by changing the layer to be the high-density wood material layer.
図１は、本発明の実施形態１に係るストランドボードの積層構造を模式的に示す斜視図である。FIG. 1 is a perspective view schematically showing a laminated structure of strand boards according to Embodiment 1 of the present invention. 図２は、本発明の実施形態２に係るストランドボードの第１例を模式的に示す斜視図である。FIG. 2 is a perspective view schematically showing a first example of a strand board according to Embodiment 2 of the present invention. 図３は、実施形態２に係るストランドボードの第１例におけるストランド層の積層状態を概略的に示す断面図である。FIG. 3 is a cross-sectional view schematically showing a layered state of strand layers in the first example of the strand board according to the second embodiment. 図４は、ストランドボードの第２例を示す図３相当図である。FIG. 4 is a view corresponding to FIG. 3 showing a second example of the strand board. 図５は、ストランドボードの第３例を示す図３相当図である。FIG. 5 is a view corresponding to FIG. 3 showing a third example of the strand board. 図６は、ストランドボードの第４例を示す図３相当図である。FIG. 6 is a view corresponding to FIG. 3 showing a fourth example of the strand board. 図７は、ストランドボードの第５例を示す図３相当図である。FIG. 7 is a view corresponding to FIG. 3 showing a fifth example of the strand board. 図８は、ストランドボードの第６例を示す図３相当図である。FIG. 8 is a view corresponding to FIG. 3 showing a sixth example of the strand board. 図９は、ストランドボードの第１例～第６例の具体的な構成を説明するための図である。FIG. 9 is a diagram for explaining a specific configuration of the first to sixth examples of the strand board. 図１０は、実施形態１に係る実施例１のストランドボードを示す断面図である。FIG. 10 is a cross-sectional view illustrating the strand board of Example 1 according to the first embodiment. 図１１は、実施例１，２及び比較例１，２の試験結果を示す図である。FIG. 11 is a diagram showing test results of Examples 1 and 2 and Comparative Examples 1 and 2. 図１２は、実施例１に係るストランドボードの密度分布を示した図である。FIG. 12 is a diagram illustrating the density distribution of the strand board according to the first embodiment. 図１３は、比較例１に係るストランドボードの密度分布を示した図である。FIG. 13 is a diagram showing the density distribution of the strand board according to Comparative Example 1. 図１４は、実施形態２に係る実施例１，２及び比較例１の曲げ試験の結果を他の物性と共に示す図である。FIG. 14 is a diagram illustrating the results of bending tests of Examples 1 and 2 and Comparative Example 1 according to Embodiment 2 together with other physical properties. 図１５は、実施例１，２及び比較例１の厚さ方向（積層方向）の密度分布を示す図である。FIG. 15 is a diagram illustrating density distributions in Examples 1 and 2 and Comparative Example 1 in the thickness direction (stacking direction). 図１６は、実施例３及び比較例２の曲げ試験及び煮沸試験の結果を他の物性と共に示す図である。FIG. 16 is a diagram showing the results of the bending test and boiling test of Example 3 and Comparative Example 2 together with other physical properties. 図１７は、実施例３及び比較例２の厚さ方向（積層方向）の密度分布を示す図である。FIG. 17 is a diagram showing the density distribution in the thickness direction (stacking direction) of Example 3 and Comparative Example 2. 図１８は、実施例４及び比較例３の曲げ試験及び煮沸試験の結果を他の物性と共に示す図である。FIG. 18 is a diagram showing the results of the bending test and boiling test of Example 4 and Comparative Example 3 together with other physical properties. 図１９は、実施例４及び比較例４の釘引き抜き試験の結果を他の物性と共に示す図である。FIG. 19 is a diagram showing the results of the nail pull-out test of Example 4 and Comparative Example 4 together with other physical properties. 図２０は、実施例４及び比較例３の厚さ方向（積層方向）の密度分布を示す図である。FIG. 20 is a diagram showing the density distribution in the thickness direction (stacking direction) of Example 4 and Comparative Example 3.
　以下、本発明の実施形態を図面に基づいて詳細に説明する。以下の好ましい実施形態の説明は、本質的に例示に過ぎず、本発明、その適用物或いはその用途を制限することを意図するものでは全くない。また、実施形態において示されている具体的数値は発明の理解を容易にするために例示するものであり、本発明の適用範囲、適用材料を限定することを意図するものではない。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or its application. In addition, specific numerical values shown in the embodiments are illustrated for facilitating understanding of the invention, and are not intended to limit the scope of application of the present invention and applicable materials.
　［実施形態１］
　図１は、本発明の実施形態１に係る木質積層材としてのストランドボードＢを模式的に示している。 [Embodiment 1]
FIG. 1 schematically shows a strand board B as a wood laminate according to Embodiment 1 of the present invention.
　この図１に示すように、ストランドボードＢは、奇数層（図１では５層）の木質材層としてのストランド層１，１，…で構成され、それらストランド層１，１，…の厚さが全て等しい例を示している。すなわち、図１の上側を表側とし、下側を裏側とした場合、表面及び裏面のストランド層１，１の厚さｗ１と、３層の中間ストランド層１，１，…の厚さｗ２，ｗ３，ｗ２とが同一である例を示している。ストランドボードＢにおけるストランド層１の積層数は奇数層に限らず、偶数層であってもよい。また、５層に限らず、４層以下であっても６層以上であってもよい。 As shown in FIG. 1, the strand board B is composed of strand layers 1, 1,... As odd-numbered layers (5 layers in FIG. 1), and the thickness of the strand layers 1, 1,. Shows an example where all are equal. That is, when the upper side in FIG. 1 is the front side and the lower side is the back side, the thickness w1 of the front and back strand layers 1, 1 and the thickness w2, w3 of the three intermediate strand layers 1, 1,. , W2 are the same. The number of layers of the strand layers 1 in the strand board B is not limited to an odd number layer, and may be an even number layer. Moreover, it is not limited to five layers, and may be four layers or less or six layers or more.
　各ストランド層１は、木材等から得られた切削片としての多数のストランド５，５，…（木質材）が集合状態になった集合体からなっている。それらストランド５，５，…の集合体が複数層に積層されて一体化されることで、複数のストランド層１，１，…が形成されている。 Each strand layer 1 is composed of an aggregate in which a large number of strands 5, 5,... (Woody material) as cutting pieces obtained from wood or the like are in an aggregated state. A plurality of strand layers 1, 1,... Are formed by laminating and integrating the strands 5, 5,.
　各ストランド５は、例えば繊維方向に沿う長さが１５０～２００ｍｍ、幅が１５～２５ｍｍ、厚さが０．３～２ｍｍ程度の薄板片又は削片である。 Each strand 5 is, for example, a thin plate or a piece having a length along the fiber direction of 150 to 200 mm, a width of 15 to 25 mm, and a thickness of about 0.3 to 2 mm.
　ストランド５に用いる樹種は特に限定されず、例えば南洋樹や広葉樹を用いてもよいし、それ以外の樹種を用いてもよい。具体的には、例えばスギ、ヒノキ、ベイマツ等のファー材、アカシア、アスペン、ポプラ、パイン系（ハードパイン、ソフトパイン、アタパイン、ラジアータパイン等）、バーチ、ゴム（ゴムの木）等が例示されるが、これらの樹種に限定されず、さらに様々な樹種を用いることができる。様々な樹種としては、サワラ、ヒバ、カヤ、栂、槙、種々の松、桐、楓、樺（白樺）、椎、ブナ、樫、樅、櫟、楢、楠、ケヤキ等の国産材、米ヒノキ、米ヒバ、米杉、米樅、スプルース、米栂、レッドウッド等の北米材、アガチス、ターミナリア、ラワン、メランチ、センゴンラウト、ジュンコン、カメレレ、カランパヤン、アンベロイ、メリナ、チーク、アピトン、センゴンラウト等の南洋材、バルサ、セドロ、マホガニー、リグナムバイタ、アカシアマンギューム、地中海松、竹、コウリャン、カメレレのような他の外材等があり、どのような材料でも使用可能である。 The tree species used for the strand 5 is not particularly limited, and for example, a southern ocean tree or a broad-leaved tree may be used, or other tree species may be used. Specifically, for example, fur materials such as cedar, hinoki and bay pine, acacia, aspen, poplar, pine (hard pine, soft pine, attapine, radiata pine, etc.), birch, rubber (rubber tree), etc. However, it is not limited to these tree species, and various tree species can be used. Various tree species include sawara, hiba, kayak, cocoon, cocoon, various pine, paulownia, cocoon, cocoon (white birch), vertebra, beech, cocoon, cocoon, cocoon, cocoon, cocoon, zelkova and other domestic timber, rice North American wood such as cypress, rice cypress, rice cedar, rice bran, spruce, rice bran, redwood, etc. There are other external materials such as South Seawood, Balsa, Cedro, Mahogany, Lignumbaita, Acacia Mangum, Mediterranean Pine, Bamboo, Kouliang, Chamelele, etc. Any material can be used.
　ストランド５の物性に関し、その密度は３００～８００ｋｇ／ｍ３程度であることが好ましく、４３０～７００ｋｇ／ｍ３であることがより好ましい。密度が３００ｋｇ／ｍ３以下であると、同密度・同強度のストランドボードＢを形成するために必要な積層マットの厚さが大きくなるとともに、後述するプレス成形工程での熱圧プレス処理に係るプレス圧を高める必要があるからである。 Relates the physical properties of the strands 5, it is preferable that the density is about 300 ~ 800kg / m 3, more preferably 430 ~ 700kg / m 3. When the density is 300 kg / m 3 or less, the thickness of the laminated mat necessary for forming the strand board B having the same density and the same strength is increased, and the hot-pressing process in the press molding process described later is applied. This is because it is necessary to increase the press pressure.
　一方、ストランド５の密度は８００ｋｇ／ｍ３を超えてもよいが、そのようなストランド５を容易に得ることが難しいからである。すなわち、８００ｋｇ／ｍ３を超えるストランド５を容易に得ることができるのであれば、密度の上限値は８００ｋｇ／ｍ３に限定されず、さらに高い値であってもよい。 On the other hand, although the density of the strand 5 may exceed 800 kg / m 3 , it is difficult to easily obtain such a strand 5. That is, if the strand 5 exceeding 800 kg / m 3 can be easily obtained, the upper limit value of the density is not limited to 800 kg / m 3 and may be a higher value.
　また、ストランド５の含水率は、２～２０％程度であることが好ましく、２～８％であることがより好ましい。含水率が２％未満の場合、プレス成形工程での熱圧プレス処理において軟化に時間がかかってプレス時間が長くなり、強度が下がる虞れがある。 The water content of the strand 5 is preferably about 2 to 20%, more preferably 2 to 8%. When the water content is less than 2%, it takes time for softening in the hot-pressing process in the press molding process, the press time becomes longer, and the strength may be lowered.
　また、ストランド５の含水率が２０％を超えると、同熱圧プレス処理において加熱・圧縮に時間がかかり、パンクし易くなるためであり、さらには接着剤の硬化が阻害されて強度が下がる虞れある。 Further, if the water content of the strand 5 exceeds 20%, it takes time to heat and compress in the same hot press process, and it becomes easy to puncture, and further, the curing of the adhesive is inhibited and the strength may be lowered. It is.
　各ストランド層１内において、ストランド５，５，…は、その繊維（図示せず）に沿った方向である繊維方向（ストランド５の長手方向）が所定の方向に沿うように配向されている。このとき、図１にも示すように、各ストランド層１内において、ストランド５，５，…の繊維は必ずしも正確に同一方向を向いている必要はない。換言すると、配向されたストランド５，５，…の繊維方向が互いに平行になっている必要はない。すなわち、繊維の方向が所定の基準方向に対してある程度（例えば２０°程度）傾いているストランド５，５，…が含まれていてもよい。 In each strand layer 1, the strands 5, 5,... Are oriented so that the fiber direction (longitudinal direction of the strands 5) along the fibers (not shown) is along a predetermined direction. At this time, as shown also in FIG. 1, the fibers of the strands 5, 5,... Do not necessarily have to face the same direction in each strand layer 1. In other words, the fiber directions of the oriented strands 5, 5,... Do not have to be parallel to each other. That is, the strands 5, 5,... Whose fiber direction is inclined to some extent (for example, about 20 °) with respect to the predetermined reference direction may be included.
　また、複数のストランド層１，１，…は、隣接するストランド層１との間でストランド５，５，…の繊維が互いに直交する方向に沿って延びるように積層されて一体化されている。すなわち、図１では、表面層のストランド層１（図１上端の層）と裏面層のストランド層１（図１下端の層）とにおいて、これらの層１，１を構成するストランド５，５，…の繊維方向が同じ方向に沿って延びている。 Further, the plurality of strand layers 1, 1,... Are stacked and integrated so that the fibers of the strands 5, 5,. That is, in FIG. 1, in the strand layer 1 (upper layer in FIG. 1) and the back strand layer 1 (lower layer in FIG. 1), the strands 5, 5, and 5 constituting these layers 1 and 1 are formed. The fiber directions of ... extend along the same direction.
　そして、この実施形態１の特徴として、ストランドボードＢにおける上記ストランド層１の積層方向（ストランドボードＢの厚さ方向）の密度分布が実質的に一定とされている。具体的には、複数のストランド層１，１，…は、該複数のストランド層１，１，…による密度の分布が積層方向の中央位置に対し面対称になるように積層されている。 As a feature of the first embodiment, the density distribution of the strand layer 1 in the strand board B in the stacking direction (the thickness direction of the strand board B) is substantially constant. Specifically, the plurality of strand layers 1, 1,... Are laminated so that the density distribution by the plurality of strand layers 1, 1,.
　次に、この実施形態１に係るストランドボードＢの製造方法について説明する。この製造方法は、ストランド生成工程、ストランド前処理工程、接着剤塗布工程、積層工程（マット形成工程）及びプレス成形工程を有する。 Next, a manufacturing method of the strand board B according to the first embodiment will be described. This manufacturing method includes a strand generation step, a strand pretreatment step, an adhesive application step, a lamination step (mat formation step), and a press molding step.
　（ストランド生成工程）
　ストランドボードＢの製造方法では、まず、多数のストランド５，５，…（木材等の切削片）を得るためのストランド生成工程を行う。この工程では、例えば切削機により丸太や間伐材等の生木を切削することで、ストランド５，５，…を生成する。尚、ストランド５，５，…は、建築現場等で発生する端材や廃材等から生成してもよいし、廃パレット材から生成することもできる。 (Strand production process)
In the manufacturing method of the strand board B, first, a strand generating step for obtaining a large number of strands 5, 5,... (Cut pieces such as wood) is performed. In this process, for example, strands 5, 5,... Are generated by cutting raw wood such as logs and thinned wood with a cutting machine. The strands 5, 5,... May be generated from scraps or waste materials generated at a construction site or the like, or may be generated from waste pallet materials.
　（ストランド前処理工程）
　上記のストランド生成工程の後、得られた多数のストランド５，５，…に対し、以下のような様々なストランド前処理工程の少なくとも１つを施すことが好ましい。この前処理は、後処理のプレス成形工程において例えば４Ｎ／ｍｍ２程度の低いプレス圧による低圧プレスを可能とするためのものであり、物理的処理方法、高周波処理方法、高温高圧処理方法、高水圧処理法、脱気・脱水繰返し処理方法、化学処理方法等の少なくとも１つを用いる。 (Strand pretreatment process)
It is preferable to perform at least one of the following various strand pretreatment steps on the obtained multiple strands 5, 5,. This pre-treatment is for enabling low-pressure pressing with a low press pressure of, for example, about 4 N / mm 2 in the post-forming press forming step. The physical treatment method, the high-frequency treatment method, the high-temperature and high-pressure treatment method, At least one of a water pressure treatment method, a degassing / dehydration repeated treatment method, a chemical treatment method, or the like is used.
　物理的処理方法は、ストランド５を物理的に圧縮処理する方法であり、ロールプレス処理方法、ビーティング処理方法、平板プレス方法等がある。まず、ロールプレス処理方法は線圧縮方法であり、図示しないが、多数のストランド５，５，…（木質材）を均一に落下するように熱圧ロールプレス装置に投入して熱圧する。そのとき、プレス条件として例えば加熱温度を室温～２００℃とし、熱圧ロール間のクリアランスを０．１～０．４ｍｍ程度とし、送り速度は５０ｍ／分程度とし、圧縮率を２０～６０％程度とする。このことにより、ストランド５を破壊することなく圧縮し、高密度化されたストランド５を得るようにしている。 The physical treatment method is a method of physically compressing the strand 5, and includes a roll press treatment method, a beating treatment method, a flat plate press method, and the like. First, the roll press treatment method is a linear compression method, and although not shown, a large number of strands 5, 5,... At that time, for example, the heating temperature is room temperature to 200 ° C., the clearance between the hot-pressing rolls is about 0.1 to 0.4 mm, the feed rate is about 50 m / min, and the compression rate is about 20 to 60%. And As a result, the strands 5 are compressed without breaking, and the densified strands 5 are obtained.
　また、ビーティング法は点圧縮方法であり、金属鍛造処理と同様に、連続的に並べられた複数のスプリングハンマー等によりストランド５を叩いて圧縮変形させる。このことにより、ロールプレス処理方法と同様に、ストランド５を破壊することなく圧縮して高密度化するようにしている。 Also, the beating method is a point compression method, and, like the metal forging process, the strands 5 are struck and compressed and deformed by a plurality of continuously arranged spring hammers. Thus, as in the roll press processing method, the strands 5 are compressed and densified without breaking.
　さらに、平板プレス方法は面圧縮方法であり、熱圧平板プレス装置にストランド５，５，…（木質材）を投入して熱圧する。プレス条件としては例えば１２０℃の温度、４Ｎ／ｍｍ２程度のプレス圧力で５分間程度とする。この方法でも、ストランド５を破壊することなく圧縮して高密度化するようにしている。 Further, the flat plate pressing method is a surface compression method, in which strands 5, 5,. The pressing conditions are, for example, a temperature of 120 ° C. and a pressing pressure of about 4 N / mm 2 for about 5 minutes. Even in this method, the strands 5 are compressed and densified without breaking.
　一方、上記高周波処理方法は、誘電体（不導体）としてのストランド５に高い周波数の電磁波（高周波）を電極間等で照射して、そのストランド５を内部から誘電加熱して軟化させる方法である。この方法により、上記物理的処理方法のようにストランド５を高密度化することなく、後処理のプレス成形工程において低いプレス圧による低圧プレスを可能としている。 On the other hand, the high-frequency treatment method is a method in which the strand 5 as a dielectric (non-conductor) is irradiated with high-frequency electromagnetic waves (high-frequency) between electrodes or the like, and the strand 5 is dielectrically heated from the inside to be softened. . This method enables low-pressure pressing with a low pressing pressure in the post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
　また、高温高圧処理方法は、ストランド５を圧力釜に入れて高温度及び高圧力を加えることにより、ストランド５（木質材）の細胞壁にダメージを与えて軟化させる方法である。その処理条件は例えば１８０℃の温度、１０Ｂａｒ程度の圧力で２分間程度とする。この方法でも、上記物理的処理方法のようにストランド５を高密度化することなく、後処理のプレス成形工程において低いプレス圧による低圧プレスを可能としている。 Also, the high-temperature and high-pressure treatment method is a method in which the strand 5 is put in a pressure vessel and a high temperature and a high pressure are applied to damage and soften the cell wall of the strand 5 (woody material). The treatment conditions are, for example, a temperature of 180 ° C. and a pressure of about 10 Bar for about 2 minutes. This method also enables low-pressure pressing with a low pressing pressure in a post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
　さらに、高水圧処理法は、ストランド５を金網等のメッシュ材中に均一にフォーミングし、そのメッシュ材を通して例えば２００ＭＰａ程度の高圧水によりストランド５の表面に微細な傷を形成する方法である。このことにより微細な破壊が生じて軟化したストランド５を得ることができる。 Furthermore, the high water pressure treatment method is a method in which the strand 5 is uniformly formed in a mesh material such as a wire mesh and fine scratches are formed on the surface of the strand 5 with high-pressure water of about 200 MPa through the mesh material. As a result, it is possible to obtain a softened strand 5 caused by fine breakage.
　また、脱気・脱水繰返し処理方法は、ストランド５を飽水状態にしてからバッチ式の釜に投入し、その釜の内部を減圧により真空状態にしてストランド５から水分を放出させることにより、ストランド５（木質材）の細胞壁の破壊を促進させて軟化させる方法である。この方法でも、上記物理的処理方法のようにストランド５を高密度化することなく、後処理のプレス成形工程において低いプレス圧による低圧プレスを可能としている。 In addition, the degassing / dehydration repeated treatment method is such that the strand 5 is saturated and then charged into a batch-type kettle, and the inside of the kettle is evacuated under reduced pressure to release moisture from the strand 5. This is a method of promoting the softening by promoting the destruction of the cell wall of 5 (wood material). This method also enables low-pressure pressing with a low pressing pressure in a post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
　そして、化学処理方法はストランド５に例えば水酸化ナトリウム等を加えてアルカリ処理を行うことにより、ストランド５そのものの可塑化を促進させて軟化させる方法である。この方法でも、上記物理的処理方法のようにストランド５を高密度化することなく、後処理のプレス成形工程において低いプレス圧による低圧プレスを可能としている。 The chemical treatment method is a method in which, for example, sodium hydroxide or the like is added to the strand 5 to perform alkali treatment, thereby promoting plasticization of the strand 5 itself and softening it. This method also enables low-pressure pressing with a low pressing pressure in a post-forming press forming step without increasing the density of the strands 5 as in the physical processing method.
　上記高周波処理方法、高温高圧処理方法、高水圧処理法、脱気・脱水繰返し処理方法、化学処理方法では、ストランド５の処理後に必要に応じて乾燥させることにより、処理後の状態が維持される。 In the high-frequency treatment method, high-temperature and high-pressure treatment method, high-water pressure treatment method, repeated degassing / dehydration treatment method, and chemical treatment method, the state after treatment is maintained by drying the strand 5 as necessary after treatment. .
　（接着剤塗布工程）
　このようにして多数のストランド５，５，…が得られると、その後、それらストランド５，５，…に接着剤を塗布する接着剤塗布工程を行う。接着剤として、例えばイソシアネート系の接着剤を用いることができ、その他、例えばフェノール樹脂、ユリア樹脂やメラミン樹脂などのアミン系接着剤を用いてもよい。 (Adhesive application process)
When a large number of strands 5, 5,... Are obtained in this way, an adhesive application step of applying an adhesive to the strands 5, 5,. As the adhesive, for example, an isocyanate-based adhesive can be used. In addition, for example, an amine-based adhesive such as a phenol resin, a urea resin, or a melamine resin may be used.
　（積層工程）
　次に、多数のストランド５，５，…を配向して積み重ねたストランド集合体を形成し、そのストランド集合体をさらに多段に積層して積層マットを形成する積層工程（マット形成工程）を行う。 (Lamination process)
Next, a strand assembly in which a large number of strands 5, 5,... Are oriented and stacked is formed, and the strand assembly is further laminated in multiple stages to form a laminated mat (mat forming step).
　具体的には、接着剤が塗布された多数のストランド５，５，…を、マット成形装置等により繊維が所定の基準方向に向くように配向させながら例えば厚さ７～１２ｍｍ程度になるまで積み重ねて、一定の厚さを有するストランド集合体を形成する。尚、ストランド集合体の厚さは上記の値に限定されず、７ｍｍ未満であっても１２ｍｍを超えてもよい。 Specifically, a large number of strands 5, 5,... Coated with an adhesive are stacked until the thickness becomes, for example, about 7 to 12 mm while the fibers are oriented so as to face a predetermined reference direction by a mat forming apparatus or the like. Thus, a strand assembly having a certain thickness is formed. The thickness of the strand aggregate is not limited to the above value, and may be less than 7 mm or more than 12 mm.
　このようにして、一定の厚さを有するストランド集合体が形成されると、その後、そのストランド集合体の上に、それとは繊維方向が例えば直交するように配向されたストランド５，５，…を積み重ねて、同様に一定の厚さを有する別のストランド集合体を形成する。 In this way, when a strand assembly having a certain thickness is formed, then strands 5, 5,... Oriented so that the fiber direction is perpendicular to the strand assembly, for example, on the strand assembly. Stack to form another strand assembly that also has a constant thickness.
　以後、上記と同様にして、ストランド集合体の積み重ねを目的の積層数（例えば５層）となるまで繰り返し、そのときに隣接するストランド集合体においてストランド５，５，…の繊維方向を互いに直交させる。このようにして積層マットを形成する。図１に示すように、５層のストランド層１，１，…からなるストランドボードＢの場合、その５層の積層マットの厚さは例えば３５～６０ｍｍ程度である。 Thereafter, in the same manner as described above, the strand assembly is repeated until the desired number of layers (for example, 5 layers) is reached, and the fiber directions of the strands 5, 5,. . In this way, a laminated mat is formed. As shown in FIG. 1, in the case of a strand board B composed of five strand layers 1, 1,..., The thickness of the five-layer laminate mat is, for example, about 35 to 60 mm.
　尚、積層マットにおけるストランド集合体の層数は、ストランドボードＢの層数に応じて決定されるものである。従って、４層以下であっても６層以上であってもよい。 The number of layers of the strand aggregate in the laminated mat is determined according to the number of layers of the strand board B. Therefore, it may be 4 layers or less or 6 layers or more.
　また、ストランド層１を構成するストランド５，５，…の密度は、複数のストランド層１，１，…間において互いに同程度であってもよいし、互いに異なる程度であってもよい。 Further, the density of the strands 5, 5,... Constituting the strand layer 1 may be the same or different from each other among the plurality of strand layers 1, 1,.
　（プレス成形工程）
　このようにして複数のストランド集合体が積層された積層マットが形成された後、この積層マットを熱圧プレス装置により所定の圧力及び温度で熱圧プレス処理して一体に成形する。この熱圧プレス処理に係るプレス圧は、例えば２～４Ｎ／ｍｍ２であり、プレス時間は例えば１０～２０分間である。尚、プレス時間は、ストランドボードＢ（完成品）の厚さによって変動するものであり、１０分未満で終了する場合もあれば、２０分以上要する場合もある。また、熱圧プレス装置による熱圧プレス処理の前に、加熱装置による予備加熱処理を行ってもよい。 (Press molding process)
After forming a laminated mat in which a plurality of strand aggregates are laminated in this way, the laminated mat is subjected to a hot-pressing process at a predetermined pressure and temperature by a hot-pressing apparatus and integrally molded. The press pressure related to this hot press process is, for example, 2 to 4 N / mm 2 , and the press time is, for example, 10 to 20 minutes. The press time varies depending on the thickness of the strand board B (finished product), and may be completed in less than 10 minutes, or may be required in 20 minutes or more. Moreover, you may perform the preheating process by a heating apparatus before the hot press process by a hot press apparatus.
　このような工程を経て、密度が７５０～９５０ｋｇ／ｍ３でありかつ曲げ強度が８０～１５０Ｎ／ｍｍ２のストランドボードＢが一体成形される。 Through these steps, the strand board B having a density of 750 to 950 kg / m 3 and a bending strength of 80 to 150 N / mm 2 is integrally formed.
　したがって、この実施形態１では、プレス成形工程における熱圧プレスのプレス圧が２～４Ｎ／ｍｍ２に低く設定される。そのため、特殊な高圧プレス機を用いることなく、高密度で高強度のストランドボードＢを得ることができる。 Therefore, in the first embodiment, the press pressure of the hot press in the press molding process is set to be low to 2-4 N / mm 2 . Therefore, a high-density and high-strength strand board B can be obtained without using a special high-pressure press.
　また、ストランドボードＢは、その表面のストランド層１及び裏面のストランド層１をそれぞれ構成するストランド５，５，…の繊維方向が互い同じであるため、ストランドボードＢの表面側及び裏面側のそれぞれ耐荷重・耐衝撃等の性能同士を同じ程度に揃えることができる。すなわち、ストランドボードＢの表裏で同等の性能を得ることができる。このことによって、ストランドボードＢはその表裏を気にすることなく使用することができるメリットが生じる。 Moreover, since the fiber directions of the strands 5, 5,... Constituting the strand layer 1 on the front surface and the strand layer 1 on the back surface are the same as each other, the strand board B has each the front side and the back side of the strand board B. Performances such as load resistance and impact resistance can be aligned to the same extent. That is, equivalent performance can be obtained on the front and back of the strand board B. This produces the merit that the strand board B can be used without worrying about its front and back.
　また、複数のストランド層１，１，…の厚さが互いに同じ程度に揃えられているため、ストランドボードＢの厚さ方向の強度特性や耐水特性等のボード性能を均一化することができる。 Further, since the thicknesses of the plurality of strand layers 1, 1,... Are equal to each other, the board performance such as strength characteristics in the thickness direction and water resistance characteristics of the strand board B can be made uniform.
　また、ストランド層１，１，…によるストランドボードＢの厚さ方向の密度の分布が面対称であるので、ストランドボードＢの表面側及び裏面側の双方で同様の性能を得ることができ、ストランドボードＢの表裏を問わずに（気にすることなく）使用できる。 Further, since the distribution of the density in the thickness direction of the strand board B by the strand layers 1, 1,... Is plane symmetric, the same performance can be obtained on both the front side and the back side of the strand board B. It can be used regardless of the front and back of board B (without concern).
　さらに、ストランド層１，１，…の積層数が奇数であると、上記と同様に、ストランドボードＢの表面側及び裏面側の双方で同様の性能を得ることができる。 Further, when the number of the strand layers 1, 1,... Is an odd number, the same performance can be obtained on both the front side and the back side of the strand board B as described above.
　尚、前述のとおり、ストランド生成工程で生成されるストランド５，５，…は、密度が４３０～７００ｋｇ／ｍ３でかつ含水率が２～２０％であること好ましい。しかし、ストランド生成工程によって得られるストランド５，５，…が当該好ましい特性から外れている場合においても、それらストランド５，５，…を利用することができる。 As described above, the strands 5, 5,... Produced in the strand producing step preferably have a density of 430 to 700 kg / m 3 and a moisture content of 2 to 20%. However, even when the strands 5, 5,... Obtained by the strand generation step deviate from the preferable characteristics, the strands 5, 5,.
　具体的には、選別機等により、切削処理後のストランドから所望の特性を有するストランド５，５，…を選別し、その選別されたストランド５，５，…を用いて、その後のストランド生成工程、ストランド前処理工程、接着剤塗布工程、積層工程（マット形成工程）及びプレス成形工程を行うようにしてもよい。 Specifically, the strands 5, 5,... Having desired characteristics are selected from the strands after the cutting process by a sorting machine or the like, and the subsequent strand generation process using the selected strands 5, 5,. The strand pretreatment step, the adhesive application step, the lamination step (mat formation step), and the press molding step may be performed.
　また、例えば接着剤塗布工程において使用する接着剤の組成や塗布方法等を工夫することにより、ストランド５，５，…の実質的な含水率や密度を調整するようにしてもよい。また、例えばプレス成形工程の熱圧プレス処理において、又は熱圧プレス処理の前に、所定のプレス処理を実施するようにしてもよい。具体的には、例えばプレス処理（圧密処理を含む）を多段階に分けることによって、熱圧プレス処理に係るストランド５，５，…の実質的な含水率を調整したり、ストランド５，５，…の実質的な密度を高めたりすることが採用される。 Further, for example, the substantial water content and density of the strands 5, 5,... May be adjusted by devising the composition and application method of the adhesive used in the adhesive application step. Further, for example, a predetermined press process may be performed in the hot press process in the press molding process or before the hot press process. Specifically, for example, the substantial moisture content of the strands 5, 5,. It is adopted to increase the substantial density of.
　［実施形態２］
　図２～図８は本発明の実施形態２を示す（尚、図１と同じ部分については同じ符号を付してその詳細な説明は省略する）。これら図２～図８は、実施形態２に係る木質積層材としてのストランドボードＢの複数の例を示しており、図２及び図３はストランドボードＢの第１例を示す。また、図４は第２例を、さらに図５は第３例を、また図６は第４例を、そして図７は第５例を、また図８は第６例をそれぞれ示している。 [Embodiment 2]
2 to 8 show a second embodiment of the present invention (note that the same parts as those in FIG. 1 are denoted by the same reference numerals and detailed description thereof is omitted). 2 to 8 show a plurality of examples of the strand board B as the wood laminate according to the second embodiment, and FIGS. 2 and 3 show a first example of the strand board B. FIG. 4 shows a second example, FIG. 5 shows a third example, FIG. 6 shows a fourth example, FIG. 7 shows a fifth example, and FIG. 8 shows a sixth example.
　上記第１例～第６例のいずれでもストランドボードＢは、複数（奇数）の木質材層としてのストランド層１，１，…を備えている。各ストランド層１は、切削片としての多数のストランド５，５，…（木質材）の集合体からなり、そのストランド５，５，…の集合体が複数積層されて一体化されることで、複数のストランド層１，１，…が形成されている。 In any of the first to sixth examples, the strand board B includes a plurality of (odd number) wood layers 1, 1,. Each strand layer 1 is composed of an aggregate of a large number of strands 5, 5,... (Wooden material) as cutting pieces, and a plurality of the aggregates of the strands 5, 5,. A plurality of strand layers 1, 1,... Are formed.
　この実施形態２では、図３～図８の上側をストランドボードＢの表側として下側を裏側とし、ストランド層１，１，…は、表側から裏側に向かって順に第１ストランド層１、第２ストランド層１、第３ストランド層１，…と番号を付す。そして、その番号を図３～図８では丸で囲んだ数字にて表している。 In Embodiment 2, the upper side of FIGS. 3 to 8 is the front side of the strand board B and the lower side is the back side, and the strand layers 1, 1,... Are in order from the front side to the back side. The strand layer 1, the third strand layer 1,. The numbers are represented by circled numbers in FIGS.
　この実施形態２の場合、各ストランド５の密度は３００～１１００ｋｇ／ｍ３程度であることが好ましい。密度が３００ｋｇ／ｍ３未満であると、高密度のストランド層１を生成するために必要な積層マットの厚さが大きくなるとともに、プレス成形工程での熱圧プレス処理に係るプレス圧を高める必要があるからである。 In the case of Embodiment 2, the density of each strand 5 is preferably about 300 to 1100 kg / m 3 . When the density is less than 300 kg / m 3, it is necessary to increase the thickness of the laminated mat necessary for producing the high-density strand layer 1 and to increase the press pressure related to the hot press process in the press forming process. Because there is.
　一方、ストランド５の密度は１１００ｋｇ／ｍ３を超えてもよいが、そのようなストランド５を容易に得ることが難しいからである。すなわち、１１００ｋｇ／ｍ３を超えるストランド５を容易に得ることができるのであれば、密度の上限値は１１００ｋｇ／ｍ３に限定されず、さらに高い値であってもよい。 On the other hand, the density of the strand 5 may exceed 1100 kg / m 3 , but it is difficult to easily obtain such a strand 5. That is, if the strand 5 exceeding 1100 kg / m 3 can be easily obtained, the upper limit value of the density is not limited to 1100 kg / m 3, and may be a higher value.
　この実施形態２においても、ストランド５，５，…は、各ストランド層１内において、その繊維に沿った方向である繊維方向が所定の方向になるように配向されている。尚、図２にも示すように、各ストランド層１内において、ストランド５，５，…の繊維は同一方向を向いている、すなわち、配向されたストランド５の繊維方向が平行になっている必要はない。換言すると、所定の基準方向に対して繊維方向がある程度傾いているストランド５が含まれていてもよい。例えば、基準方向に対して配向方向が２０°程度傾いているストランド５が含まれていてもよい。 Also in the second embodiment, the strands 5, 5,... Are oriented in each strand layer 1 so that the fiber direction, which is the direction along the fiber, is a predetermined direction. As shown in FIG. 2, in each strand layer 1, the fibers of the strands 5, 5,... Are oriented in the same direction, that is, the fiber directions of the oriented strands 5 need to be parallel. There is no. In other words, the strand 5 in which the fiber direction is inclined to some extent with respect to the predetermined reference direction may be included. For example, the strand 5 in which the orientation direction is inclined by about 20 ° with respect to the reference direction may be included.
　この実施形態２の特徴として、実施形態１とは異なり、ストランドボードＢにおける奇数のストランド層１，１，…のうちの少なくとも１層が、他のストランド層１ｂよりも密度の高い高密度ストランド層１ａとされ、残りの他のストランド層１ｂは低密度ストランド層とされている。この実施形態２における「ストランド層の密度」とは、ストランド５そのものの密度ではなく、それらの集合体であるストランド層１自体の密度を指している。 As a feature of the second embodiment, unlike the first embodiment, at least one of the odd-numbered strand layers 1, 1,... In the strand board B has a higher density than the other strand layers 1b. The remaining strand layer 1b is a low-density strand layer. The “density of the strand layer” in the second embodiment refers not to the density of the strand 5 itself but to the density of the strand layer 1 itself that is an aggregate thereof.
　以下、具体的にストランドボードＢの各例について詳細に説明する。尚、図３～図８では、高密度ストランド層１ａは密な点集合で表し、低密度ストランド層１ｂは粗い点集合で表している。 Hereinafter, each example of the strand board B will be specifically described in detail. 3 to 8, the high-density strand layer 1a is represented by a dense point set, and the low-density strand layer 1b is represented by a coarse point set.
　（第１例）
　図２及び図３は実施形態２に係るストランドボードＢの第１例を示す。このストランドボードＢは、第１～第５の５層のストランド層１，１，…からなる。それらのストランド層１，１，…の各々は、隣接するストランド層１との間でストランド５，５の繊維が互いに直交する方向に延びるように積層されて一体化されている。そして、ストランドボードＢの表側端に位置する図３上端の第１ストランド層１と、裏側端に位置する図３下端の第５ストランド層１とにおけるストランド５，５の繊維方向は互いに同じ方向である。 (First example)
2 and 3 show a first example of the strand board B according to the second embodiment. The strand board B includes first to fifth five strand layers 1, 1,... Each of the strand layers 1, 1,... Is laminated and integrated with the adjacent strand layer 1 so that the fibers of the strands 5 and 5 extend in directions orthogonal to each other. The fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end in FIG. 3 located at the front end of the strand board B and the fifth strand layer 1 at the lower end in FIG. is there.
　また、５層のストランド層１，１，…のうちの２層は、その密度が他の３層よりも高い高密度ストランド層１ａとなっており、後者は低密度ストランド層１ｂとなっている。２層の高密度ストランド層１ａ，１ａは互いに密度が同じで、例えば１０００ｋｇ／ｍ３（平均値）である。一方、３層の低密度ストランド層１ｂ，１ｂ，…も互いに密度が同じで、例えば８００ｋｇ／ｍ３である。この低密度ストランド層１ｂの密度は、通常一般に成形されるストランドボードの密度と同程度である。 Two of the five strand layers 1, 1,... Are high-density strand layers 1a whose density is higher than the other three layers, and the latter is a low-density strand layer 1b. . The two high-density strand layers 1a and 1a have the same density, for example, 1000 kg / m 3 (average value). On the other hand, the three low- density strand layers 1b, 1b,... Have the same density, for example, 800 kg / m 3 . The density of the low-density strand layer 1b is approximately the same as the density of the strand board that is usually formed.
　具体的には、ストランドボードＢの表側端部に位置する第１ストランド層１、裏側端部に位置する第５ストランド層１、及び厚さ方向中央部に位置する第３ストランド層１がいずれも低密度ストランド層１ｂである。これら表裏端部及び厚さ方向中央部を除いた部分に位置する第２及び第４ストランド層１，１が共に高密度ストランド層１ａとされている。 Specifically, the first strand layer 1 located at the front side end of the strand board B, the fifth strand layer 1 located at the back side end, and the third strand layer 1 located at the center in the thickness direction are all. It is the low density strand layer 1b. Both the second and fourth strand layers 1 and 1 located at portions excluding the front and back end portions and the central portion in the thickness direction are high-density strand layers 1a.
　また、５層のストランド層１，１，…の厚さは異なっていて３つに分けられている。ストランドボードＢ全体の厚さに対して、第１及び第５ストランド層１，１（低密度ストランド層１ｂ）の各厚さが例えば２５％を、また第２及び第４ストランド層１，１（高密度ストランド層１ａ）の各厚さが例えば２０％を、さらに第３ストランド層１（低密度ストランド層１ｂ）の厚さが例えば１０％をそれぞれ占めている。このことでストランドボードＢの全体に対する高密度ストランド層１ａの厚さは例えば４０％となっている。また、５層のストランド層１，１，…は、それらのストランド層１，１，…による密度の分布がストランドボードＢの積層方向、すなわち厚さ方向の中央位置に対して面対称になるように積層されている。尚、ストランドボードＢの総厚さは例えば２８ｍｍである。 Also, the five strand layers 1, 1,... Have different thicknesses and are divided into three. The thickness of each of the first and fifth strand layers 1 and 1 (low-density strand layer 1b) is, for example, 25% of the total thickness of the strand board B, and the second and fourth strand layers 1 and 1 ( Each thickness of the high-density strand layer 1a) occupies, for example, 20%, and the thickness of the third strand layer 1 (low-density strand layer 1b) occupies, for example, 10%. Accordingly, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 40%. In addition, the five strand layers 1, 1,... Are arranged so that the density distribution by the strand layers 1, 1,... Is plane-symmetric with respect to the lamination position of the strand board B, that is, the center position in the thickness direction. Are stacked. The total thickness of the strand board B is 28 mm, for example.
　ここで、実施形態２に係るストランドボードＢを製造する方法について説明する。尚、この製造方法は、第１例のストランドボードＢだけでなく、第２例～第６例の各ストランドボードＢを製造する場合も同様である。 Here, a method for manufacturing the strand board B according to the second embodiment will be described. This manufacturing method is the same when manufacturing not only the strand board B of the first example but also the strand boards B of the second to sixth examples.
　この実施形態２の製造方法は、基本的に実施形態１と同じである。従って、実施形態１と同じ部分の説明は省略し、異なる部分だけ詳細に説明する。 The manufacturing method of the second embodiment is basically the same as that of the first embodiment. Therefore, description of the same part as Embodiment 1 is abbreviate | omitted, and only a different part is demonstrated in detail.
　すなわち、この製造方法は、ストランド生成工程、ストランド前処理工程、接着剤塗布工程、積層工程（マット形成工程）及びプレス成形工程を有する。そのうち、ストランド前処理工程、接着剤塗布工程、プレス成形工程は実施形態１と同じである
　そして、この実施形態２では、マット形成工程において、ストランドの集合体上に別のストランド集合体を積み重ねて積層マットを形成するとき、高密度ストランド層１ａにしようとするストランド集合体については、その各ストランド５の密度を、低密度ストランド層１ｂとなるストランド集合体のストランド５の密度よりも高くする。そうすることで、高密度ストランド層１ａ及び低密度ストランド層１ｂを混在させて一体的に積層することができる。 That is, this manufacturing method has a strand production | generation process, a strand pre-processing process, an adhesive agent coating process, a lamination process (mat formation process), and a press molding process. Among them, the strand pretreatment process, the adhesive application process, and the press molding process are the same as those in the first embodiment. In the second embodiment, in the mat forming process, another strand aggregate is stacked on the strand aggregate. When the laminated mat is formed, the density of each strand 5 of the strand aggregate to be the high-density strand layer 1a is set higher than the density of the strand 5 of the strand aggregate that becomes the low-density strand layer 1b. By doing so, the high density strand layer 1a and the low density strand layer 1b can be mixed and laminated together.
　例えば、最初のストランド生成工程において、予め、通常一般の範囲の密度を有するストランドと、それよりも高い密度を有するストランドとの２種類を用意しておく。そして、低密度層ストランド層１ｂとなるストランド集合体については、そのストランド５として、通常一般の範囲の密度を有するものを用いる。それに対し、高密度ストランド層１ａとなるストランド集合体にあっては、そのストランド５として、圧縮等によって通常一般の範囲よりも高い密度としたものを用いるようにしてもよい。 For example, in the first strand generation step, two types of strands, that is, a strand having a density in a general general range and a strand having a density higher than that are prepared in advance. And about the strand aggregate | assembly used as the low density layer strand layer 1b, what has the density of a normal general range is used as the strand 5. FIG. On the other hand, in the strand aggregate used as the high-density strand layer 1a, the strand 5 may have a density higher than the normal range by compression or the like.
　また、高密度ストランド層１ａとなるストランド集合体のストランド５と、低密度層ストランド層１ｂとなるストランド集合体のストランド５との間で樹種等を異ならせ、高密度ストランド層１ａとなるストランド集合体のストランド５は、低密度層ストランド層１ｂとなるストランド集合体のストランド５よりも密度の高い樹種を用いるようにしてもよい。 Also, the strand aggregates that become the high-density strand layer 1a are made different from the strand 5 of the strand aggregate that becomes the high-density strand layer 1a and the strand 5 of the strand aggregate that becomes the low-density layer strand layer 1b. As the strand 5 of the body, a tree species having a higher density than the strand 5 of the strand assembly that becomes the low-density layer strand layer 1b may be used.
　また、積層マットが形成された後、この積層マットを熱圧プレス装置により所定の圧力及び温度で熱圧プレス処理して一体に成形するプレス成形工程において、その熱圧プレス処理に係るプレス圧は実施形態１と同様に例えば２～４Ｎ／ｍｍ２であるが、プレス時間は例えば１０～３０分間である。尚、この実施形態２でも、プレス時間は、ストランドボードＢ（完成品）の厚さによって変動するものであり、１０分未満で終了する場合もあれば、３０分以上要する場合もある。また、熱圧プレス装置による熱圧プレス処理の前に、加熱装置による予備加熱処理を行ってもよい。 In addition, after the laminated mat is formed, in the press molding process in which the laminated mat is hot-pressed at a predetermined pressure and temperature by a hot-pressing apparatus and integrally molded, the press pressure related to the hot-pressing process is The pressure is, for example, 2 to 4 N / mm 2 as in the first embodiment, but the pressing time is, for example, 10 to 30 minutes. In the second embodiment as well, the pressing time varies depending on the thickness of the strand board B (finished product), and may be completed in less than 10 minutes, or may be required in 30 minutes or more. Moreover, you may perform the preheating process by a heating apparatus before the hot press process by a hot press apparatus.
　尚、前述のとおり、ストランド生成工程で生成されるストランド５は、密度が３００～１１００ｋｇ／ｍ３でかつ含水率が２～８％であること好ましいが、この好ましい特性から外れているストランドでも利用することができる。 As described above, the strand 5 produced in the strand production step preferably has a density of 300 to 1100 kg / m 3 and a moisture content of 2 to 8%. can do.
　（第２例）
　図４はストランドボードＢの第２例を示す。このストランドボードＢは、第１例と同様に、第１～第５の５層のストランド層１，１，…からなる。それらのストランド層１，１，…の各々は、隣接するストランド層１との間でストランド５の繊維が互いに直交する方向に延びるように積層されて一体化されている。ストランドボードＢの表側端に位置する図４上端の第１ストランド層１と、裏側端に位置する図４下端の第５ストランド層１とにおけるストランド５，５の繊維方向は互いに同じである。 (Second example)
FIG. 4 shows a second example of the strand board B. The strand board B is composed of first to fifth five strand layers 1, 1,..., As in the first example. Each of the strand layers 1, 1,... Is laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1. The fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end of FIG. 4 located at the front side end of the strand board B and the fifth strand layer 1 at the lower end of FIG.
　５層のストランド層１，１，…のうちの２層は高密度ストランド層１ａとなっており、他の３層は、高密度ストランド層１ａよりも密度の低い低密度ストランド層１ｂとなっている。２層の高密度ストランド層１ａ，１ａは互いに密度が同じで、例えば１１００ｋｇ／ｍ３（平均値）であり、この密度は第１例の高密度ストランド層１ａよりも高くなっている。一方、３層の低密度ストランド層１ｂ，１ｂ，…も互いに密度が同じであり、この密度は第１例の低密度ストランド層１ｂよりも低い（ストランドボードＢの製品密度が第１例より低いため）。 Two of the five strand layers 1, 1,... Are high-density strand layers 1a, and the other three layers are low-density strand layers 1b having a lower density than the high-density strand layers 1a. Yes. The two high-density strand layers 1a and 1a have the same density, for example, 1100 kg / m 3 (average value), and this density is higher than the high-density strand layer 1a of the first example. On the other hand, the three low- density strand layers 1b, 1b,... Have the same density, and this density is lower than the low-density strand layer 1b of the first example (the product density of the strand board B is lower than that of the first example). For).
　上記第１例とは異なり、ストランドボードＢの表側端部に位置する第１ストランド層１と、裏側端部に位置する第５ストランド層１とが高密度ストランド層１ａとされている。残りの厚さ方向の中間部に位置する第２～第４ストランド層１，１，…は低密度ストランド層１ｂとなっている。 Unlike the first example, the first strand layer 1 located at the front end of the strand board B and the fifth strand layer 1 located at the back end are the high-density strand layer 1a. The second to fourth strand layers 1, 1,... Located in the remaining intermediate portion in the thickness direction are low-density strand layers 1b.
　また、５層のストランド層１，１，…の厚さはいずれも同じで、ストランドボードＢ全体の厚さに対して各ストランド層１の厚さが例えば２０％ずつを占めている。このことでストランドボードＢの全体に対する高密度ストランド層１ａの厚さは例えば４０％となっている。また、５層のストランド層１，１，…は、それらのストランド層１，１，…による密度の分布がストランドボードＢの厚さ方向の中央位置に対し面対称になるように積層されている。尚、ストランドボードＢの総厚さは例えば９ｍｍである。 The thicknesses of the five strand layers 1, 1,... Are the same, and the thickness of each strand layer 1 occupies, for example, 20% of the total thickness of the strand board B. Accordingly, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 40%. Further, the five strand layers 1, 1,... Are laminated so that the density distribution by the strand layers 1, 1,... Is symmetrical with respect to the center position in the thickness direction of the strand board B. . The total thickness of the strand board B is 9 mm, for example.
　（第３例）
　図５はストランドボードＢの第３例を示す。このストランドボードＢは、第２例とは異なり、第１～第７の７層のストランド層１，１，…からなる。それらのストランド層１，１，…は、隣接するストランド層１との間でストランド５の繊維が互いに直交する方向に延びるように積層されて一体化されている。ストランドボードＢの表側端に位置する図５上端の第１ストランド層１と、裏側端に位置する図５下端の第７ストランド層１とにおけるストランド５，５の繊維方向は互いに同じである。 (Third example)
FIG. 5 shows a third example of the strand board B. FIG. Unlike the second example, the strand board B is composed of first to seventh seven strand layers 1, 1,. The strand layers 1, 1,... Are laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1. The fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end of FIG. 5 located at the front side end of the strand board B and the seventh strand layer 1 at the lower end of FIG.
　７層のストランド層１，１，…のうちの２層は高密度ストランド層１ａとなっている。他の５層は、高密度ストランド層１ａよりも密度の低い低密度ストランド層１ｂとなっている。２層の高密度ストランド層１ａ，１ａは互いに密度が同じで、例えば１０００ｋｇ／ｍ３（平均値）であり、この密度は第１例の高密度ストランド層１ａと同じである。一方、５層の低密度ストランド層１ｂ，１ｂ，…も互いに密度が同じであり、この密度は第１例の低密度ストランド層１ｂよりも低い（ストランドボードＢの製品密度が第１例より低いため）。 Two of the seven strand layers 1, 1,... Are high-density strand layers 1a. The other five layers are low density strand layers 1b having a density lower than that of the high density strand layers 1a. The two high-density strand layers 1a and 1a have the same density, for example, 1000 kg / m 3 (average value), and this density is the same as the high-density strand layer 1a of the first example. On the other hand, the five low- density strand layers 1b, 1b,... Have the same density, and this density is lower than the low-density strand layer 1b of the first example (the product density of the strand board B is lower than that of the first example). For).
　具体的には、ストランドボードＢの表側端部に位置する第１ストランド層１と、裏側端部に位置する第７ストランド層１とが高密度ストランド層１ａとされている。残りの厚さ方向の中間部に位置する第２～第６ストランド層１，１，…はいずれも低密度ストランド層１ｂとなっている。 Specifically, the first strand layer 1 located at the front side end of the strand board B and the seventh strand layer 1 located at the back side end constitute the high-density strand layer 1a. The second to sixth strand layers 1, 1,... Located in the remaining intermediate portion in the thickness direction are all low-density strand layers 1b.
　また、７層のストランド層１，１，…の厚さは異なっていて２つに分けられている。ストランドボードＢ全体の厚さに対して、第１及び第７ストランド層１，１（高密度ストランド層１ａ）の各厚さが例えば１５％を、また第２、第３、第５及び第６ストランド層１，１，…（低密度ストランド層１ｂ）の各厚さが例えば１５％を、さらに第４ストランド層１（低密度ストランド層１ｂ）の厚さが例えば１０％をそれぞれ占めている。このことでストランドボードＢの全体に対する高密度ストランド層１ａの厚さは例えば３０％となっている。また、７層のストランド層１，１，…は、それらのストランド層１，１，…による密度の分布がストランドボードＢの厚さ方向の中央位置に対し面対称になるように積層されている。尚、ストランドボードＢの総厚さは例えば１２ｍｍである。 Also, the seven strand layers 1, 1,... Have different thicknesses and are divided into two. The thickness of each of the first and seventh strand layers 1 and 1 (high-density strand layer 1a) is, for example, 15% with respect to the entire thickness of the strand board B, and the second, third, fifth and sixth Each thickness of the strand layers 1, 1,... (Low density strand layer 1b) occupies, for example, 15%, and further, the thickness of the fourth strand layer 1 (low density strand layer 1b) occupies, for example, 10%. Accordingly, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 30%. Further, the seven strand layers 1, 1,... Are laminated so that the density distribution of the strand layers 1, 1,... Is plane-symmetric with respect to the center position in the thickness direction of the strand board B. . The total thickness of the strand board B is 12 mm, for example.
　（第４例）
　図６はストランドボードＢの第４例を示す。このストランドボードＢは、第２例や第３例とは異なり、第１～第３の３層のストランド層１，１，…からなっている。それらストランド層１，１，…は、隣接するストランド層１との間でストランド５の繊維が互いに直交する方向に延びるように積層されて一体化されている。ストランドボードＢの表側端に位置する図６上端の第１ストランド層１と、裏側端に位置する図６下端の第３ストランド層１とにおけるストランド５，５の繊維方向は互いに同じである。 (Fourth example)
FIG. 6 shows a fourth example of the strand board B. Unlike the second and third examples, the strand board B includes first to third three strand layers 1, 1,. The strand layers 1, 1,... Are laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1. The fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end of FIG. 6 located at the front side end of the strand board B and the third strand layer 1 at the lower end of FIG.
　３層のストランド層１，１，…のうちの１層が高密度ストランド層１ａとなっている。他の２層は、高密度ストランド層１ａよりも密度の低い低密度ストランド層１ｂとなっている。１層の高密度ストランド層１ａの密度は例えば８００ｋｇ／ｍ３（平均値）であり、第２例の高密度ストランド層１ａよりも低くなっている。一方、低密度層である２層のストランド層１ｂ，１ｂも互いに密度が同じであり、この密度は第１例の低密度ストランド層１ｂと同じである。 One of the three strand layers 1, 1,... Is a high-density strand layer 1a. The other two layers are a low density strand layer 1b having a lower density than the high density strand layer 1a. The density of one high-density strand layer 1a is, for example, 800 kg / m 3 (average value), which is lower than the high-density strand layer 1a of the second example. On the other hand, the two strand layers 1b and 1b, which are low density layers, have the same density, and this density is the same as the low density strand layer 1b of the first example.
　具体的には、ストランドボードＢの厚さ方向の中央部（中間部）に位置する第２ストランド層１のみが高密度ストランド層１ａとされ、表裏側端部に位置する第１及び第３ストランド層１，１は低密度ストランド層１ｂとなっている。 Specifically, only the second strand layer 1 located at the center portion (intermediate portion) in the thickness direction of the strand board B is the high-density strand layer 1a, and the first and third strands located at the front and back side end portions. Layers 1 and 1 are low density strand layers 1b.
　また、３層のストランド層１，１，…の厚さは異なっていて２つに分けられている。ストランドボードＢ全体の厚さに対して、第１及び第３ストランド層１，１（低密度ストランド層１ｂ）の各厚さが例えば２０％を、また第２ストランド層１（高密度ストランド層１ａ）の厚さが例えば６０％をそれぞれ占めている。このことでストランドボードＢの全体に対する高密度ストランド層１ａの厚さは例えば６０％となっている。また、３層のストランド層１，１，…は、それらのストランド層１，１，…による密度の分布がストランドボードＢの厚さ方向の中央位置に対し面対称になるように積層されている。尚、ストランドボードＢの総厚さは例えば１８ｍｍである。 Also, the three strand layers 1, 1,... Have different thicknesses and are divided into two. The thickness of each of the first and third strand layers 1 and 1 (low density strand layer 1b) is, for example, 20% of the total thickness of the strand board B, and the second strand layer 1 (high density strand layer 1a). ) Occupies 60%, for example. Accordingly, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 60%. Further, the three strand layers 1, 1,... Are laminated so that the density distribution of the strand layers 1, 1,... Is symmetrical with respect to the center position in the thickness direction of the strand board B. . The total thickness of the strand board B is 18 mm, for example.
　（第５例）
　図７はストランドボードＢの第５例を示す。このストランドボードＢは、第４例と同様に第１～第３の３層のストランド層１，１，…からなる。それらのストランド層１，１，…は、第１例～第４例と異なり、隣接するストランド層１との間でストランド５の繊維が平行な方向に延びるように積層されて一体化されている。すなわち、ストランドボードＢの表側端に位置する図７上端の第１ストランド層１と、裏側端に位置する図７下端の第３ストランド層１とにおけるストランド５，５の繊維方向は互いに同じ方向である。また、ストランドボードＢの厚さ方向の中央部に位置する第２ストランド層１におけるストランド５の繊維方向も第１及び第３ストランド層１，１のストランド５，５の繊維方向と同じである。 (Fifth example)
FIG. 7 shows a fifth example of the strand board B. FIG. This strand board B is composed of first to third three strand layers 1, 1,... As in the fourth example. Unlike the first to fourth examples, the strand layers 1, 1,... Are laminated and integrated so that the fibers of the strands 5 extend in parallel directions between the adjacent strand layers 1. . That is, the fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end of FIG. 7 positioned at the front side end of the strand board B and the third strand layer 1 at the lower end of FIG. is there. Further, the fiber direction of the strand 5 in the second strand layer 1 located at the center portion in the thickness direction of the strand board B is also the same as the fiber direction of the strands 5 and 5 of the first and third strand layers 1 and 1.
　第４例とは異なり、３層のストランド層１，１，…のうちの２層は高密度ストランド層１ａとなっており、他の１層は低密度ストランド層１ｂとなっている。２層の高密度ストランド層１ａ，１ａは、密度が例えば８００ｋｇ／ｍ３（平均値）であり、この密度は第４例の高密度ストランド層１ａと同じである。一方、１層の低密度ストランド層１ｂの密度は、第１例の低密度ストランド層１ｂよりも低い（ストランドボードＢの製品密度が第１例より低いため）。 Unlike the fourth example, two of the three strand layers 1, 1,... Are high-density strand layers 1a, and the other one is a low-density strand layer 1b. The two high-density strand layers 1a and 1a have a density of, for example, 800 kg / m 3 (average value), and this density is the same as the high-density strand layer 1a of the fourth example. On the other hand, the density of one low-density strand layer 1b is lower than that of the first example low-density strand layer 1b (because the product density of the strand board B is lower than that of the first example).
　具体的には、ストランドボードＢの表裏側端部に位置する第１及び第３ストランド層１，１は高密度ストランド層１ａとされ、厚さ方向の中央部に位置する第２ストランド層１のみが低密度ストランド層１ｂとなっている。 Specifically, the first and third strand layers 1, 1 located at the front and back end portions of the strand board B are high-density strand layers 1 a, and only the second strand layer 1 located at the center in the thickness direction. Is a low density strand layer 1b.
　また、３層のストランド層１，１，…の厚さは異なっていて２つに分けられている。ストランドボードＢ全体の厚さに対して、第１及び第３ストランド層１，１（高密度ストランド層１ａ）の各厚さが例えば４０％を、また第２ストランド層１（低密度ストランド層１ｂ）の厚さが例えば２０％をそれぞれ占めている。このことでストランドボードＢの全体に対する高密度ストランド層１ａの厚さは例えば８０％となっている。また、３層のストランド層１，１，…は、それらのストランド層１，１，…による密度の分布がストランドボードＢの厚さ方向の中央位置に対し面対称になるように積層されている。尚、ストランドボードＢの総厚さは例えば１５ｍｍである。 Also, the three strand layers 1, 1,... Have different thicknesses and are divided into two. The thickness of each of the first and third strand layers 1 and 1 (high-density strand layer 1a) is, for example, 40% of the total thickness of the strand board B, and the second strand layer 1 (low-density strand layer 1b). ) Occupies, for example, 20%. Thus, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 80%. In addition, the three strand layers 1, 1,... Are laminated so that the density distribution by the strand layers 1, 1,. . The total thickness of the strand board B is 15 mm, for example.
　（第６例）
　図８はストランドボードＢの第６例を示す。このストランドボードＢは、第１例と同様に、第１～第５の５層のストランド層１，１，…からなる。それらのストランド層１，１，…の各々は、隣接するストランド層１との間でストランド５の繊維が互いに直交する方向に延びるように積層されて一体化されている。ストランドボードＢの表側端に位置する図８上端の第１ストランド層１と、裏側端に位置する図８下端の第５ストランド層１とにおけるストランド５，５の繊維方向は互いに同じである。 (Sixth example)
FIG. 8 shows a sixth example of the strand board B. FIG. The strand board B is composed of first to fifth five strand layers 1, 1,..., As in the first example. Each of the strand layers 1, 1,... Is laminated and integrated so that the fibers of the strand 5 extend in a direction orthogonal to each other between the adjacent strand layers 1. The fiber directions of the strands 5 and 5 in the first strand layer 1 at the upper end of FIG. 8 located at the front side end of the strand board B and the fifth strand layer 1 at the lower end of FIG.
　５層のストランド層１，１，…のうちの３層は高密度ストランド層１ａとなっている。他の２層は、高密度ストランド層１ａよりも密度の低い低密度ストランド層１ｂとなっている。３層の高密度ストランド層１ａ，１ａ，…は互いに密度が同じで、例えば１０００ｋｇ／ｍ３（平均値）であり、この密度は第１例の高密度ストランド層１ａと同じである。一方、２層の低密度ストランド層１ｂ，１ｂも互いに密度が同じであり、この密度は第１例の低密度ストランド層１ｂと同じである。 Three of the five strand layers 1, 1,... Are high-density strand layers 1a. The other two layers are a low density strand layer 1b having a lower density than the high density strand layer 1a. The three high density strand layers 1a, 1a,... Have the same density, for example, 1000 kg / m 3 (average value), and this density is the same as the high density strand layer 1a of the first example. On the other hand, the two low-density strand layers 1b and 1b have the same density, and this density is the same as the low-density strand layer 1b of the first example.
　具体的には、第２例とは逆に、ストランドボードＢの厚さ方向の中間部に位置する第２～第４ストランド層１，１，…は高密度ストランド層１ａとされている。残りの表側端部に位置する第１ストランド層１と、裏側端部に位置する第５ストランド層１とが低密度ストランド層１ｂとなっている。 Specifically, contrary to the second example, the second to fourth strand layers 1, 1,... Located in the middle portion of the strand board B in the thickness direction are high-density strand layers 1a. The first strand layer 1 located at the remaining front end and the fifth strand layer 1 located at the rear end constitute a low density strand layer 1b.
　また、５層のストランド層１，１，…の厚さは異なっていて３つに分けられている。ストランドボードＢ全体の厚さに対して、第１及び第５ストランド層１，１（低密度ストランド層１ｂ）の各厚さが例えば３０％を、また第２及び第４ストランド層１，１（高密度ストランド層１ａ）の各厚さが例えば１５％を、さらに第３ストランド層１（高密度ストランド層１ａ）の厚さが例えば１０％をそれぞれ占めている。このことでストランドボードＢの全体に対する高密度ストランド層１ａの厚さは例えば６０％となっている。また、５層のストランド層１，１，…は、それらのストランド層１，１，…による密度の分布がストランドボードＢの厚さ方向の中央位置に対し面対称になるように積層されている。尚、ストランドボードＢの総厚さは例えば２８ｍｍである。 Also, the five strand layers 1, 1,... Have different thicknesses and are divided into three. The thickness of each of the first and fifth strand layers 1 and 1 (low density strand layer 1b) is, for example, 30% with respect to the total thickness of the strand board B, and the second and fourth strand layers 1 and 1 ( Each thickness of the high-density strand layer 1a) occupies, for example, 15%, and further, the thickness of the third strand layer 1 (high-density strand layer 1a) occupies, for example, 10%. Accordingly, the thickness of the high-density strand layer 1a with respect to the entire strand board B is, for example, 60%. Further, the five strand layers 1, 1,... Are laminated so that the density distribution by the strand layers 1, 1,... Is symmetrical with respect to the center position in the thickness direction of the strand board B. . The total thickness of the strand board B is 28 mm, for example.
　以上の第１例～第６例についての具体的な構成を図９に示している。 A specific configuration of the first to sixth examples is shown in FIG.
　したがって、この実施形態２においては、ストランドボードＢが複数層のストランド層１，１，…からなり、それらのうちの一部（１層～３層）のストランド層１が他のストランド層１よりも密度の高い高密度ストランド層１ａとされている。そのため、その高密度ストランド層１ａによってストランドボードＢの高強度及び高耐水性能が実現できるようになり、高強度で高い耐水性能を有するストランドボードＢが得られる。 Therefore, in the second embodiment, the strand board B is composed of a plurality of strand layers 1, 1,..., And a part (1 to 3 layers) of the strand layers 1 is more than the other strand layers 1. Is a high-density strand layer 1a having a high density. Therefore, the high-strength strand layer 1a can realize the high strength and high water resistance of the strand board B, and the strand board B having high strength and high water resistance can be obtained.
　また、ストランドボードＢにおけるストランド層１の密度を高くして高密度ストランド層１ａとする場合、例えばその高密度ストランド層１ａのストランド５のみを高密度にすればよく、全てのストランド層１，１，…のストランド５を高密度にすることは不要となる。その分、プレス機によるプレス時間が短くなり、プレス圧力も低くなり、生産性を向上させることができるとともに、成形時のパンクを防止することもできる。 Further, when the density of the strand layer 1 in the strand board B is increased to form the high-density strand layer 1a, for example, only the strands 5 of the high-density strand layer 1a may be increased in density. It is not necessary to increase the density of the strands 5. Accordingly, the press time by the press machine is shortened, the press pressure is lowered, the productivity can be improved, and the puncture at the time of molding can be prevented.
　さらに、ストランドボードＢの奇数のストランド層１，１，…のうちの１層ないし３層が高密度ストランド層１ａであることから、上記第１例～第６例に示すように、複数のストランド層１，１，…の中から高密度ストランド層１ａとすべき層を必要に応じて選択することができる。このように、高密度ストランド層１ａの位置の変更によってストランドボードＢの特性として種々のバリエーションが得られ、各例特有の効果を奏することができる。 Further, since one to three of the odd-numbered strand layers 1, 1,... Of the strand board B are high-density strand layers 1a, a plurality of strands are provided as shown in the first to sixth examples. A layer to be the high-density strand layer 1a can be selected from the layers 1, 1,. Thus, various variations can be obtained as the characteristics of the strand board B by changing the position of the high-density strand layer 1a, and effects specific to each example can be achieved.
　すなわち、例えば図２及び図３に示す第１例や図８に示す第６例では、ストランドボードＢの表裏端部と厚さ方向中央部とを除いた部分に位置する第２及び第４ストランド層１，１が高密度ストランド層１ａとされ、残りの表裏端部と厚さ方向中央部とに位置する第１、第３及び第５ストランド層１，１，…が密度の低い低密度ストランド層１ｂである。このようにすると、表裏部の低密度ストランド層１ｂによって成形時のプレス圧力を低減できるとともに、ストランドボードＢに打たれる固定具としての釘に対する引き抜き抵抗（力）を高密度ストランド層１ａによって増大させることができる利点がある。特に、図８に示す第６例では、生産性がより一層上がる効果を奏することができる。 That is, for example, in the first example shown in FIGS. 2 and 3 and the sixth example shown in FIG. 8, the second and fourth strands located in the portion excluding the front and back end portions and the thickness direction central portion of the strand board B. The layers 1, 1 are high-density strand layers 1a, and the first, third, and fifth strand layers 1, 1,... Located at the remaining front and back end portions and the thickness direction central portion are low-density strands with low density. Layer 1b. If it does in this way, while being able to reduce the press pressure at the time of shaping | molding by the low density strand layer 1b of a front and back part, the extraction resistance (force) with respect to the nail as a fixing tool struck by the strand board B is increased by the high density strand layer 1a. There are advantages that can be made. In particular, in the sixth example shown in FIG. 8, the effect of further increasing productivity can be achieved.
　また、図４に示す第２例や図５に示す第３例では、ストランドボードＢの表裏端部に位置するストランド層１，１が高密度ストランド層１ａとされ、中間部に位置するストランド層１，１，…が低密度ストランド層１ｂである。このような構造では、表裏部の高密度ストランド層１ａによって、ストランドボードＢの曲げ強度を増大させることができるとともに、その表裏部の耐水性能を向上させることができる。 Further, in the second example shown in FIG. 4 and the third example shown in FIG. 5, the strand layers 1 and 1 located at the front and back end portions of the strand board B are the high-density strand layers 1 a and the strand layers located at the intermediate portion. 1, 1,... Are low density strand layers 1b. In such a structure, the high-strength strand layer 1a on the front and back portions can increase the bending strength of the strand board B and improve the water resistance of the front and back portions.
　さらに、図６に示す第４例では、ストランドボードＢの表裏中間部に位置するストランド層１が高密度ストランド層１ａとされ、他の部分に位置するストランド層１，１が低密度ストランド層１ｂである。このような構造では、その高密度ストランド層１ａにより中間部の密度が高くなってストランドボードＢの厚さ方向全体から見た密度分布を均一にすることができる。また、ストランドボードＢの厚さ方向中間部に高密度ストランド層１ａが配置され、表裏部は低密度ストランド層１ｂであるので、成形時のパンクを有効に防止して生産性を向上させることができる。 Furthermore, in the 4th example shown in FIG. 6, the strand layer 1 located in the front and back intermediate part of the strand board B is made into the high density strand layer 1a, and the strand layers 1 and 1 located in other parts are the low density strand layer 1b. It is. In such a structure, the density of the intermediate portion is increased by the high-density strand layer 1a, and the density distribution seen from the entire thickness direction of the strand board B can be made uniform. Moreover, since the high density strand layer 1a is arrange | positioned in the thickness direction intermediate part of the strand board B, and the front and back part is the low density strand layer 1b, it can prevent the puncture at the time of shaping | molding effectively and can improve productivity. it can.
　また、図７に示す第５例では、ストランドボードＢの表裏中央部に位置するストランド層１が高密度ストランド層１ａとされ、ストランドボードＢの表裏側端に位置する第１及び第３ストランド層１，１が低密度ストランド層１ｂとされている。さらに、第１～第３ストランド層１，１，…の全てにおけるストランド５，５，…の繊維方向が互いに同じ方向である。このように構造にすると、その繊維方向に沿った曲げ強度を増大させ、剪断強度をも増大させることができる。 Further, in the fifth example shown in FIG. 7, the strand layer 1 located at the front and back center portions of the strand board B is the high-density strand layer 1 a, and the first and third strand layers located at the front and back side ends of the strand board B 1, 1 is the low-density strand layer 1b. Further, the fiber directions of the strands 5, 5,... In all of the first to third strand layers 1, 1,. With such a structure, the bending strength along the fiber direction can be increased, and the shear strength can also be increased.
　そして、この実施形態２におけるストランドボードＢの第１例～第４例では、各ストランド層１におけるストランド５，５，…の繊維が互いに同じ方向に延び、かつ隣接するストランド層１のストランド５の繊維が互いに直交する方向に延びている。こうすると、第５例のように、ストランド５の繊維が全てのストランド層１，１，…の全体に亘って同じ方向に延びている場合と比較して、様々な方向からの力の作用に対し高い強度を実現することができ、ストランド層１の積層数が増加するほど上記繊維方向の違いによる強度の差がより顕著になる。 In the first to fourth examples of the strand board B in the second embodiment, the fibers of the strands 5, 5,... In each strand layer 1 extend in the same direction, and the strands 5 of the adjacent strand layers 1 The fibers extend in directions perpendicular to each other. In this case, as in the fifth example, compared to the case where the fibers of the strand 5 extend in the same direction over all the strand layers 1, 1,. On the other hand, high strength can be realized, and the difference in strength due to the difference in the fiber direction becomes more remarkable as the number of strand layers 1 is increased.
　これに対し、第５例のように、積層方向全体に亘ってストランド５，５の配向方向が同じ場合、上述のように、特定の方向からの力の作用に対し高い強度を実現することができる。 On the other hand, as in the fifth example, when the orientation directions of the strands 5 and 5 are the same throughout the laminating direction, as described above, high strength can be realized against the action of force from a specific direction. it can.
　また、この実施形態２においても、ストランド層１，１，…によるストランドボードＢの厚さ方向の密度の分布が面対称であるので、ストランドボードＢの表面側及び裏面側の双方で同様の性能を得ることができ、ストランドボードＢの表裏を問わずに使用できる。 Also in the second embodiment, since the distribution of the density in the thickness direction of the strand board B by the strand layers 1, 1,... Is plane-symmetric, the same performance is obtained on both the front side and the back side of the strand board B. Can be obtained regardless of the front and back of the strand board B.
　しかも、ストランドボードＢは奇数のストランド層１，１，…が積層されたものであるので、ストランドボードＢの表面側及び裏面側の双方で同様の性能を得ることができる。 Moreover, since the strand board B is a laminate of odd-numbered strand layers 1, 1,..., The same performance can be obtained on both the front side and the back side of the strand board B.
　［その他の実施形態］
　尚、本発明は上記実施形態１，２に限定されない。上記実施形態１では、複数のストランド層１，１，…の厚さｗ１～ｗ３が全て同一とされているが、これに限定されず、各層１の厚さｗ１～ｗ３は任意に設定することができる。 [Other Embodiments]
The present invention is not limited to the first and second embodiments. In the first embodiment, the thicknesses w1 to w3 of the plurality of strand layers 1, 1,... Are all the same. However, the present invention is not limited to this, and the thicknesses w1 to w3 of each layer 1 are arbitrarily set. Can do.
　例えば複数のストランド層１，１，…は、厚さ方向（積層方向）の内側の層から外側の層に向かって次第に厚さが増すように構成されていてもよい。つまり、図１において複数のストランド層１，１，…の厚さが、ｗ１＞ｗ２＞ｗ３の関係となっていてもよい。このように、荷重や衝撃を受け易く、また湿度等の影響を受け易い外側（表裏側）のストランド層１の厚さを他のストランド層１よりも厚くすることで、ストランドボードＢにおける外部環境からの影響に対する性能を高めることができる。 For example, the plurality of strand layers 1, 1,... May be configured so that the thickness gradually increases from the inner layer in the thickness direction (lamination direction) toward the outer layer. That is, in FIG. 1, the thicknesses of the plurality of strand layers 1, 1,... May have a relationship of w1> w2> w3. Thus, the external environment in the strand board B can be increased by making the thickness of the outer (front and back) strand layer 1 that is susceptible to load and impact and also susceptible to humidity and the like to be thicker than the other strand layers 1. The performance against the influence from can be improved.
　また、複数のストランド層１，１，…の厚さが互いに異なっていてもよい。例えば表面及び裏面の２層のストランド層１，１の厚さｗ１と、中間の３層のストランド層１，１，…の厚さｗ２，ｗ３とが異なる値であってもよい。また、図示しないが、５層全てのストランド層１，１，…の厚さが互いに異なっていてもよい。 Further, the thicknesses of the plurality of strand layers 1, 1,... May be different from each other. For example, the thickness w1 of the two strand layers 1, 1 on the front surface and the back surface may be different from the thickness w2, w3 of the three intermediate strand layers 1, 1,. Although not shown, the thicknesses of all five strand layers 1, 1,... May be different from each other.
　また、上記実施形態１では、全てのストランド層１，１，…において、そのストランド５，５，…の繊維方向が、隣接するストランド層１のストランド５，５，…の繊維方向と直交しているが、これに限定されない。例えば複数のストランド層１，１，…のうち、一部の隣接するストランド層１，１のストランド５，５，…の繊維方向が同一であってもよい。また、例えば長さや密度等の形態が互いに異なるストランド５，５，…を含むストランド層１，１が互いに隣接配置されている場合に、この隣接するストランド層１，１のストランド５，５，…の繊維方向が同一であってもよい。 In the first embodiment, in all the strand layers 1, 1,..., The fiber directions of the strands 5, 5,... Are orthogonal to the fiber directions of the strands 5, 5,. However, it is not limited to this. For example, among the plurality of strand layers 1, 1,..., The strands 5, 5,. For example, when the strand layers 1, 1 including strands 5, 5,... Having different shapes such as length and density are arranged adjacent to each other, the strands 5, 5,. The fiber directions may be the same.
　さらに、上記実施形態１において、ストランドボードＢの各ストランド層１を構成するストランド５（木質材）の密度や厚さをストランド層１，１，…間で互いに異ならせるようにしてもよい。 Furthermore, in the first embodiment, the density and thickness of the strands 5 (wood materials) constituting each strand layer 1 of the strand board B may be different between the strand layers 1, 1,.
　例えば、積層工程（マット形成工程）において、複数のストランド５，５，…の集合体を積み重ねる際に、各ストランド集合体のストランド５自体の相対的な密度が、厚さ方向の外側のストランド層１から内側のストランド層１に向かって次第に増すように積み重ねてもよい。一般的に、プレス成形工程において、積層マットのプレス処理を実施すると、プレス機の圧力が直接与えられる外側のストランド層１の方が内側のストランド層１と比較して、相対的な密度が高まる傾向にある。そのため、このように、プレス処理の前において、予め内側のストランド層１のストランド５の相対的な密度を外側のストランド層１よりも高くすることによって、プレス処理後において、ストランドボードＢの積層方向の密度分布を均一化することができるようになる。この場合において、各ストランド層１を構成するストランド５の樹種は、互いに異ならせてもよいし、互いに同じであってもよい。 For example, when stacking a plurality of strands 5, 5,... In the stacking step (mat forming step), the relative density of the strands 5 of each strand assembly is the outer strand layer in the thickness direction. The layers may be stacked so as to gradually increase from 1 toward the inner strand layer 1. In general, when the laminated mat is pressed in the press molding process, the outer strand layer 1 to which the press machine pressure is directly applied has a higher relative density than the inner strand layer 1. There is a tendency. Therefore, in this way, before the pressing process, the relative density of the strands 5 of the inner strand layer 1 is set higher than that of the outer strand layer 1 in advance, so that the strand board B is laminated in the stacking direction after the pressing process. The density distribution can be made uniform. In this case, the tree species of the strands 5 constituting each strand layer 1 may be different from each other or the same.
　すなわち、一部又は全てのストランド層１において、各ストランド層１のストランド５の樹種、厚さ、密度等を必要な特性やコスト等に応じて適宜選択することができる。 That is, in some or all of the strand layers 1, the tree type, thickness, density, and the like of the strands 5 of each strand layer 1 can be appropriately selected according to necessary characteristics and costs.
　また、実施形態１の積層工程（マット形成工程）において、複数のストランド層１，１，…のうちの少なくとも１層が高密度のストランド５，５，…で構成されるようにストランド集合体を積み重ねてもよい。このストランド層１は、他のストランド層１よりも相対的に密度の高いストランド５で構成された層である。具体的には、例えばストランドボードＢが奇数層のストランド層１を有する場合において、表面側又は裏面側から見て奇数番目のストランド層１が当該高密度のストランド５で構成されるように積層してもよい。また、例えばストランドボードＢの用途、求められる強度特性、その他の性能等に応じて、複数のストランド層１，１，…のうちの特定のストランド層１（少なくとも１層）が高密度のストランド５，５，…で構成されるように積層してもよい。尚、高密度ストランド５，５，…で構成されるストランド層１が複数ある場合に、それらストランド層１，１，…の密度及び厚さが互いに異なっていてもよい。 Further, in the laminating step (mat forming step) of the first embodiment, the strand assembly is formed so that at least one of the plurality of strand layers 1, 1,. May be stacked. The strand layer 1 is a layer composed of strands 5 having a relatively higher density than the other strand layers 1. Specifically, for example, when the strand board B has the odd-numbered strand layers 1, the odd-numbered strand layers 1 as viewed from the front side or the back side are laminated so as to be composed of the high-density strands 5. May be. Further, for example, depending on the use of the strand board B, required strength characteristics, other performances, etc., the specific strand layer 1 (at least one layer) of the plurality of strand layers 1, 1,. , 5,... When there are a plurality of strand layers 1 composed of high- density strands 5, 5,..., The density and thickness of the strand layers 1, 1,.
　また、上記実施形態２では、ストランドボードＢが奇数のストランド層１，１，…を備えているものとしているが、ストランド層１の積層数は偶数であってもよい。しかし、ストランドボードＢの表面側及び裏面側の双方で同様の性能が得られるようにできる点では奇数の方が好ましい。 Moreover, in the said Embodiment 2, although the strand board B shall be provided with the odd number of strand layers 1, 1, ..., the lamination | stacking number of the strand layers 1 may be an even number. However, the odd number is preferable in that the same performance can be obtained on both the front surface side and the back surface side of the strand board B.
　また、上記実施形態２では、各ストランド層１におけるストランド６の繊維を互いに同じとし、隣接するストランド層１のストランド５，５の繊維方向が直交するか平行になるようにしたが、これに限定されず、各ストランド層１のストランド５の繊維方向は自由に選択することができる。 In Embodiment 2 described above, the fibers of the strands 6 in each strand layer 1 are the same as each other, and the fiber directions of the strands 5 and 5 of the adjacent strand layers 1 are orthogonal or parallel to each other. The fiber direction of the strand 5 of each strand layer 1 can be freely selected.
　また、上記実施形態１，２では、ストランド５の集合体をボード状に積層したストランドボードＢについて説明したが、本発明はこのようなストランドボードＢに限定されない。例えば厚さ及び幅に大きな差がない断面矩形状（角材状）の複数のストランド層が積層されていてもよく、その場合、ストランド材（木質積層材）は、複数のストランド層が積層された根太や柱等にすることができる。 In the first and second embodiments, the strand board B in which the aggregates of the strands 5 are laminated in a board shape has been described. However, the present invention is not limited to such a strand board B. For example, a plurality of strand layers having a rectangular cross-section (square material shape) with no significant difference in thickness and width may be laminated. In that case, the strand material (wood laminate) is a laminate of a plurality of strand layers. It can be a joist or a pillar.
　さらに、上記実施形態１，２は、集合状態の複数のストランド５，５，…で構成された複数のストランド層１，１，…が積層された状態で一体化されたストランドボードＢの例である。しかし、本発明は、例えば合板やＬＶＬ（Laminated Veneer Lumber）であっても適用することができる。具体的には、ストランド５の集合体に代えて単板とすればよい。すなわち、合板やＬＶＬの場合、各木質材層はそれぞれ少なくとも１枚の単板によって構成される。 Further, the first and second embodiments are examples of the strand board B that is integrated in a state where a plurality of strand layers 1, 1,. is there. However, the present invention can be applied to, for example, plywood or LVL (Laminated Veneer Lumber). Specifically, a single plate may be used instead of the aggregate of strands 5. That is, in the case of plywood or LVL, each wood material layer is composed of at least one single plate.
　この木質積層材が合板やＬＶＬの場合、その製造方法は一般的な合板やＬＶＬの製造方法を採用することができる。具体的には、切削機により丸太や間伐材等の生木を切削して単板を生成する。次いで、複数枚の単板を単板間に接着剤を介在させた状態で、ＬＶＬでは隣接する単板の繊維方向が同じ方向に、また合板では隣接する単板の繊維方向が互いに直交する方向にそれぞれ積層する。その後、単板の積層体を冷圧プレス・熱圧プレスにより成形して接着剤を硬化させればよい。 When the wood laminate is plywood or LVL, a general plywood or LVL manufacturing method can be adopted as the manufacturing method. Specifically, a single board is generated by cutting raw wood such as logs and thinned wood with a cutting machine. Next, in the state where a plurality of single plates have an adhesive interposed between the single plates, the fiber directions of adjacent single plates in LVL are the same direction, and in the case of plywood, the fiber directions of adjacent single plates are orthogonal to each other. Each is laminated. Thereafter, the adhesive may be cured by forming a laminate of single plates by cold pressing or hot pressing.
　そのとき、実施形態１のように、木質材層の積層方向の密度分布を実質的に一定にする場合には、例えばプレス成形工程で成形される前に、予め各単板の密度や厚さ等を設定すればよい。 At that time, as in the first embodiment, when the density distribution in the stacking direction of the wood material layer is made substantially constant, for example, before the molding in the press molding process, the density and thickness of each single plate are preliminarily formed. Etc. may be set.
　一方、実施形態２のように、木質材層を高密度木質材層と低密度木質材層との組み合わせにする場合には、やはり例えばプレス成形工程で成形される前に、予め一部の木質材層において、各木質材層を構成する木質材の密度を樹種等によって他の木質材層よりも高くすればよい。 On the other hand, when the wood material layer is a combination of a high-density wood material layer and a low-density wood material layer as in the second embodiment, a part of the wood material is preliminarily formed, for example, before being formed in the press molding process. In the material layer, the density of the wood material constituting each wood material layer may be made higher than that of other wood material layers depending on the type of tree.
　次に、上記実施形態１及び２に係るストランドボードについて、具体的に実施した実施例について説明する。尚、実施形態１及び２にそれぞれ係る「実施例」や「比較例」は、その番号が同じであっても互いに異なっており、各実施形態毎に特定されたものである。 Next, specific examples of the strand boards according to the first and second embodiments will be described. The “example” and “comparative example” according to the first and second embodiments are different from each other even if the numbers are the same, and are specified for each embodiment.
　［実施形態１について］
　（実施例１）
　繊維方向に沿う長さが１５０～２００ｍｍ、幅が１５～２５ｍｍ、厚さが０．８～２ｍｍで、密度が５００～６００ｋｇ／ｍ３のヒノキ製の多数のストランドの集合体を積層して５層のストランド層からなる３７ｍｍ厚の積層マットを形成した。その後、プレス温度１４０℃及びプレス圧４Ｎ／ｍｍ２で１０分間の熱圧プレスを行い、密度８１８ｋｇ／ｍ３、厚さ１２．４ｍｍのストランドボードを得た。これが実施例１である。 [About Embodiment 1]
Example 1
A length of 150 to 200 mm along the fiber direction, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm and a density of 500 to 600 kg / m 3 of a large number of cypress strands are laminated to form 5 A laminated mat having a thickness of 37 mm composed of multiple strand layers was formed. Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 4 N / mm 2 for 10 minutes to obtain a strand board having a density of 818 kg / m 3 and a thickness of 12.4 mm. This is Example 1.
　その実施例１の外観写真を図１０に示す。尚、図１０中、Ｂはストランドボード、１はストランド層である。また、この実施例１について曲げ試験、寸法変化試験及び吸水試験を行った結果を図１１に示す。さらに、密度分布測定装置（ELECTRONIC WOOD SYSTEMSGMBH社製の「DENSE-LAB X」）を用いて、ストランドボードの厚さ方向（積層方向）の密度分布を測定した結果を図１２に示す。 The appearance photograph of Example 1 is shown in FIG. In FIG. 10, B is a strand board and 1 is a strand layer. Moreover, the result of having done the bending test, the dimensional change test, and the water absorption test about this Example 1 is shown in FIG. Furthermore, the result of measuring the density distribution in the thickness direction (stacking direction) of the strand board using a density distribution measuring apparatus (“DENSE-LAB® X” manufactured by ELECTRONIC® WOOD® SYSTEMSGMBH) is shown in FIG.
　（実施例２）
　繊維方向に沿う長さが１５０～２００ｍｍ、幅が１５～２５ｍｍ、厚さが０．８～２ｍｍで、密度が４５０～５５０ｋｇ／ｍ３のベイマツ製の多数のストランドの集合体を積層して５層のストランド層からなる３６ｍｍ厚の積層マットを形成した。その後、プレス温度１４０℃及びプレス圧４Ｎ／ｍｍ２で１０分間の熱圧プレスを行い、密度８３２ｋｇ／ｍ３、厚さ１２．２ｍｍのストランドボードを得、それを実施例２とした。この実施例２について曲げ試験、寸法変化試験及び吸水試験を行った結果を同じ図１１に示す。 (Example 2)
An assembly of a large number of strands made of bay pine having a length along the fiber direction of 150 to 200 mm, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm, and a density of 450 to 550 kg / m 3 is laminated. A laminated mat having a thickness of 36 mm composed of a plurality of strand layers was formed. Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 4 N / mm 2 for 10 minutes to obtain a strand board having a density of 832 kg / m 3 and a thickness of 12.2 mm. The results of a bending test, a dimensional change test, and a water absorption test for Example 2 are shown in FIG.
　（比較例１）
　繊維方向に沿う長さが１５０～２００ｍｍ、幅が１５～２５ｍｍ、厚さが０．８～２ｍｍで、密度が４００～５００ｋｇ／ｍ３のヒノキ製の多数のストランドの集合体を積層して５層のストランド層からなる４２ｍｍ厚の積層マットを形成した。その後、プレス温度１４０℃及びプレス圧８Ｎ／ｍｍ２で１０分間の熱圧プレスを行い、密度７７９ｋｇ／ｍ３、厚さ１２．７ｍｍのストランドボードを得、それを比較例１とした。この比較例１について曲げ試験、寸法変化試験及び吸水試験を行った結果を同じ図１１に示す。さらに、密度分布測定装置（DENSE-LAB X、ELECTRONIC WOOD SYSTEMSGMBH社製）を用いて、ストランドボードの厚さ方向（積層方向）の密度分布を測定した結果を図１３に示す。 (Comparative Example 1)
A length of 150 to 200 mm along the fiber direction, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm and a density of 400 to 500 kg / m 3 of a large number of cypress strands are laminated to form 5 A laminated mat having a thickness of 42 mm composed of a single strand layer was formed. Thereafter, hot pressing was performed for 10 minutes at a pressing temperature of 140 ° C. and a pressing pressure of 8 N / mm 2 to obtain a strand board having a density of 779 kg / m 3 and a thickness of 12.7 mm. The results of a bending test, a dimensional change test, and a water absorption test for Comparative Example 1 are shown in FIG. Furthermore, the result of having measured the density distribution of the thickness direction (lamination direction) of a strand board using the density distribution measuring apparatus (DENSE-LAB X, ELECTRONIC WOOD SYSTEMSGMBH company) is shown in FIG.
　（比較例２）
　繊維方向に沿う長さが１５０～２００ｍｍ、幅が１５～２５ｍｍ、厚さが０．８～２ｍｍで、密度が３５０～４５０ｋｇ／ｍ３のベイマツ製の多数のストランドの集合体を積層して５層のストランド層からなる３５ｍｍ厚の積層マットを形成した。その後、プレス温度１４０℃及びプレス圧８Ｎ／ｍｍ２で１０分間の熱圧プレスを行い、密度８１２ｋｇ／ｍ３、厚さ１２．４ｍｍのストランドボードを得、それを比較例２とした。この比較例２について曲げ試験、寸法変化試験及び吸水試験を行った結果を同じ図１１に示す。 (Comparative Example 2)
An aggregate of a large number of strands made of bay pine having a length along the fiber direction of 150 to 200 mm, a width of 15 to 25 mm, a thickness of 0.8 to 2 mm, and a density of 350 to 450 kg / m 3 is laminated to 5 A laminated mat having a thickness of 35 mm composed of a single strand layer was formed. Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 8 N / mm 2 for 10 minutes to obtain a strand board having a density of 812 kg / m 3 and a thickness of 12.4 mm. The results of a bending test, a dimensional change test, and a water absorption test for Comparative Example 2 are shown in FIG.
　図１１の結果を考察するに、実施例１は比較例１に比べて、密度が高く、曲げ強度、ＭＯＲ（Modulus of Rupture）、ＭＯＥ（Modulus of Elasticity）がいずれも高いことが判る。寸法変化率、吸水率は、実施例１と比較例１とで同等の値である。同様に、実施例２は比較例２に比べて、密度が高く、曲げ強度、ＭＯＲがほぼ同等で、ＭＯＥが高いことが判る。寸法変化率、吸水率は、実施例２と比較例２とで同等の値である。 Referring to the results of FIG. 11, it can be seen that Example 1 has a higher density and higher bending strength, MOR (Modulus of Rupture) and MOE (Modulus of Elasticity) than Comparative Example 1. The dimensional change rate and the water absorption rate are the same values in Example 1 and Comparative Example 1. Similarly, it can be seen that Example 2 has a higher density, bending strength and MOR are substantially the same, and MOE is higher than that of Comparative Example 2. The dimensional change rate and the water absorption rate are the same values in Example 2 and Comparative Example 2.
　また、図１２及び図１３の結果を考察するに、実施例１は比較例１に比べて、複数のストランド層の積層方向の密度分布が実質的に一定であることが判る。密度分布が実質的に一定であるとは、例えば図１２及び図１３に示すように、密度分布の測定結果に変動がある場合に、その各図で破線にて示す中間値の変化が少なくて中間値が実質的に一定であることを含むものとする。例えば、図１２（実施例１）に示す破線と、図１３（比較例１）に示す破線とを比較した場合、図１２に示す密度分布の中間値の方が変動が少なく、中間値は略一定の値となっている。 Also, considering the results of FIGS. 12 and 13, it can be seen that the density distribution in the stacking direction of the plurality of strand layers in Example 1 is substantially constant as compared with Comparative Example 1. The density distribution is substantially constant, for example, as shown in FIGS. 12 and 13, when there is a change in the measurement result of the density distribution, there is little change in the intermediate value indicated by the broken line in each figure. It is assumed that the intermediate value is substantially constant. For example, when the broken line shown in FIG. 12 (Example 1) is compared with the broken line shown in FIG. 13 (Comparative Example 1), the intermediate value of the density distribution shown in FIG. It is a constant value.
　このように密度分布が実質的に一定であることにより、密度分布のむらがなく、ストランドボード全体としての耐水性・強度（せん断強度等）が向上する。具体的には、密度が低い部分は、密度が高い部分と比較して耐水性能、強度が劣る。そのため、密度分布のむらがあると、密度が低い部分の耐水性能及び強度によりストランドボード全体の性能が律則される。これに対し、密度分布が略一定の場合には、そのような性能のボトルネックとなるような部分をなくすことができる。 As described above, since the density distribution is substantially constant, there is no uneven density distribution, and the water resistance and strength (shear strength, etc.) of the entire strand board are improved. Specifically, the portion with low density is inferior in water resistance and strength as compared with the portion with high density. Therefore, if the density distribution is uneven, the performance of the entire strand board is regulated by the water resistance and strength of the portion where the density is low. On the other hand, when the density distribution is substantially constant, a portion that becomes a bottleneck of such performance can be eliminated.
　尚、上記曲げ試験は、IICL_Floor_Performance TB001 Ver.2に準じて行った。寸法変化試験及び吸水試験は、合板の日本農林規格の煮沸繰り返し試験に準じて行った。 The above bending test was performed according to IICL_Floor_Performance TB001 Ver.2. The dimensional change test and the water absorption test were conducted in accordance with the repeated boiling test of Japanese agricultural and forestry standards for plywood.
　［実施形態２について］
　（実施例１）
　厚さが０．８ｍｍで、密度が３００～６００ｋｇ／ｍ３のアスペン製の多数のストランドの集合体を積層して５層のストランド層からなる厚さ５３ｍｍの積層マットを形成した。その５層のストランド層のうち、実施形態２におけるストランドボードの第２例（図４参照）と同様に、積層方向の中間部に位置する第２～第４ストランド層のストランドは、通常一般の密度（平均値３９３ｋｇ／ｍ３）のものを用いた。また、積層方向の両端部に位置する第１及び第５ストランド層のストランドについては、通常一般よりも密度が高い（平均値５５７ｋｇ／ｍ３）ものを用いた。 [About Embodiment 2]
Example 1
An aggregate of a large number of strands made of aspen having a thickness of 0.8 mm and a density of 300 to 600 kg / m 3 was laminated to form a laminated mat having a thickness of 53 mm consisting of five strand layers. Of the five strand layers, as in the second example of the strand board in the second embodiment (see FIG. 4), the strands of the second to fourth strand layers located at the intermediate portion in the stacking direction are generally ordinary strands. The one having a density (average value 393 kg / m 3 ) was used. Moreover, about the strand of the 1st and 5th strand layer located in the both ends of the lamination direction, the density (average value 557 kg / m < 3 >) whose density is higher than usual is used.
　その後、プレス温度１６０℃及びプレス圧４Ｎ／ｍｍ２で８分間の熱圧プレスを行い、ストランドボードを得、それを実施例１とした。このプレス時の目標厚さ到達時間は２４秒であった。 Thereafter, hot pressing was performed at a pressing temperature of 160 ° C. and a pressing pressure of 4 N / mm 2 for 8 minutes to obtain a strand board, which was designated as Example 1. The target thickness arrival time at the time of pressing was 24 seconds.
　（実施例２）
　実施例１と同様に、５層のストランド層からなる厚さ５２ｍｍの積層マットを形成した。その５層のストランド層のうち、積層方向の両端部に位置する第１及び第５ストランド層のストランドについては、実施例１よりも密度が高い（平均値８０５ｋｇ／ｍ３）ものを用いた。その後、実施例１と同様の条件で熱圧プレスを行い、ストランドボードを得、それを実施例２とした。このプレス時の目標厚さ到達時間は１２秒であった。他は実施例１と同じである。 (Example 2)
In the same manner as in Example 1, a laminated mat having a thickness of 52 mm composed of five strand layers was formed. Among the five strand layers, the strands of the first and fifth strand layers located at both ends in the stacking direction were higher in density than Example 1 (average value 805 kg / m 3 ). Thereafter, hot pressing was performed under the same conditions as in Example 1 to obtain a strand board, which was designated as Example 2. The target thickness arrival time at the time of pressing was 12 seconds. Others are the same as Example 1.
　（比較例１）
　実施例１と同様に、５層のストランド層からなる厚さ６２ｍｍの積層マットを形成した。その５層のストランド層は、全て通常一般の密度（平均値３９３ｋｇ／ｍ３）のものを用いた。その後、実施例１と同様の条件で熱圧プレスを行い、ストランドボードを得、それを実施例１とした。プレス時の目標厚さ到達時間は３３秒であった。他は実施例１と同じである。 (Comparative Example 1)
In the same manner as in Example 1, a laminated mat having a thickness of 62 mm composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 393 kg / m 3 ). Then, the hot press was performed on the conditions similar to Example 1, the strand board was obtained, and it was set as Example 1. The target thickness arrival time during pressing was 33 seconds. Others are the same as Example 1.
　（試験Ａ）
　上記実施例１，２及び比較例１の各々について常態曲げ試験（曲げ試験のスパンは２２５ｍｍ）を行った。その結果を他の物性と共に図１４に示す。 (Test A)
Each of Examples 1 and 2 and Comparative Example 1 was subjected to a normal bending test (the bending test span was 225 mm). The results are shown in FIG. 14 together with other physical properties.
　また、上記の密度分布測定装置（ELECTRONIC WOOD SYSTEMSGMBH社製の「DENSE-LAB X」）を用いて、ストランドボードの厚さ方向（積層方向）の密度分布を測定した。その結果を図１５に示す。 Further, the density distribution in the thickness direction (stacking direction) of the strand board was measured using the above-described density distribution measuring apparatus (“DENSE-LAB® X” manufactured by ELECTRONIC WOOD WOOD SYSTEMSGMBH). The result is shown in FIG.
　図１４の結果を考察するに、実施例１及び実施例２と比較例１との比較により、５層のストランド層のうちの表裏の第１及び第５ストランド層を高密度ストランド層とすることで、プレス前の積層マットの厚さ（かさ高さ）は小さくなり、プレス時にも積層マットが潰れ易くなって目標値に達するまでのプレス時間（目標厚さ到達時間）が短くなっている。また、常態曲げ試験による曲げ特性については、ＭＯＲ、ＭＯＥは実施例１及び実施例２のいずれも比較例１と同等である。 In consideration of the result of FIG. 14, by comparing Example 1 and Example 2 with Comparative Example 1, the first and fifth strand layers on the front and back of the five strand layers are made to be high-density strand layers. Thus, the thickness (bulk height) of the laminated mat before pressing becomes small, and the pressing time (target thickness reaching time) until the laminated mat is easily crushed and reaches the target value also during pressing is shortened. Further, regarding the bending characteristics by the normal bending test, MOR and MOE are the same as those in Comparative Example 1 in both Example 1 and Example 2.
　（実施例３）
　厚さが０．８ｍｍで、密度が３００～６００ｋｇ／ｍ３のアスペン製の多数のストランドの集合体を積層して５層のストランド層からなる厚さ７０ｍｍの積層マットを形成した。その５層のストランド層のうち、実施形態２におけるストランドボードの第１例（図３参照）と同様に、積層方向の中間部に位置する第２及び第４ストランド層を除く第１、第３及び第５ストランド層のストランドは、通常一般の密度（平均値３９３ｋｇ／ｍ３）のものを用いた。また、第２及び第４ストランド層のストランドについては、通常一般よりも密度が高い（平均値９３３ｋｇ／ｍ３）ものを用いた。 (Example 3)
An assembly of a large number of strands made of aspen having a thickness of 0.8 mm and a density of 300 to 600 kg / m 3 was laminated to form a laminated mat having a thickness of 70 mm composed of five strand layers. Of the five strand layers, as in the first example of the strand board in the second embodiment (see FIG. 3), the first and third strands excluding the second and fourth strand layers located in the intermediate portion in the stacking direction. As the strands of the fifth strand layer, those having a general density (average value of 393 kg / m 3 ) were used. Moreover, about the strand of a 2nd and 4th strand layer, the density (average value of 933 kg / m < 3 >) whose density is higher than usual is used.
　その後、プレス温度１４０℃及びプレス圧４Ｎ／ｍｍ２で１０分間の熱圧プレスを行い、密度８４６ｋｇ／ｍ３、厚さ１２．５ｍｍのストランドボードを得、それを実施例３とした。ＭＤＩ添加率は１２％である。 Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 4 N / mm 2 for 10 minutes to obtain a strand board having a density of 846 kg / m 3 and a thickness of 12.5 mm. The MDI addition rate is 12%.
　（比較例２）
　実施例３と同様にして、５層のストランド層からなる厚さ７８ｍｍの積層マットを形成した。その５層のストランド層は、全て通常一般の密度（平均値３９３ｋｇ／ｍ３）のものを用いた。その後、プレス温度１４０℃及びプレス圧８Ｎ／ｍｍ２で１０分間の熱圧プレスを行い、密度８４８ｋｇ／ｍ３、厚さ１２．６ｍｍのストランドボードを得、それを比較例２とした。他は実施例３と同じである。 (Comparative Example 2)
In the same manner as in Example 3, a laminated mat having a thickness of 78 mm composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 393 kg / m 3 ). Thereafter, hot pressing was performed at a pressing temperature of 140 ° C. and a pressing pressure of 8 N / mm 2 for 10 minutes to obtain a strand board having a density of 848 kg / m 3 and a thickness of 12.6 mm. Others are the same as Example 3.
　（試験Ｂ）
　上記実施例３及び比較例２について常態曲げ試験及び煮沸試験を行った。煮沸試験は、合板の日本農林規格の煮沸繰り返し試験に準じて行い、２回の煮沸試験後の吸水厚さ膨張率ＴＳ、吸水率ＷＡ及び剥離強度ＩＢを調べた。その結果を他の物性と共に図１６に示す。 (Test B)
About the said Example 3 and the comparative example 2, the normal bending test and the boiling test were done. The boiling test was performed in accordance with the boiling repeated test of Japanese Agricultural Standards for plywood, and the water absorption thickness expansion coefficient TS, the water absorption coefficient WA, and the peel strength IB after two boiling tests were examined. The results are shown in FIG. 16 together with other physical properties.
　また、試験Ａと同様に、密度分布測定装置を用いて、ストランドボードの厚さ方向（積層方向）の密度分布を測定した結果を図１７に示す。 Moreover, the result of measuring the density distribution in the thickness direction (stacking direction) of the strand board using the density distribution measuring device as in Test A is shown in FIG.
　図１６の結果を考察するに、５層のストランド層のうちの積層方向中間部に位置する第２及び第４ストランド層を高密度ストランド層とした実施例３と、５層の全層を低密度ストランド層とした比較例２とを比較したとき、実施例３の曲げ強度や煮沸試験後の剥離強度は比較例２と同じかそれを上回っており、比較例２よりも低下していない。 Considering the results of FIG. 16, Example 3 in which the second and fourth strand layers located in the intermediate portion in the stacking direction of the five strand layers are the high-density strand layers, and all the five layers are low. When compared with Comparative Example 2 in which the density strand layer was compared, the bending strength of Example 3 and the peel strength after the boiling test were the same as or higher than those of Comparative Example 2 and were not lower than those of Comparative Example 2.
　そして、５層のストランド層のうちの第２及び第４ストランド層を高密度ストランド層とすることで、比較例２のような高いプレス圧（８Ｎ／ｍｍ２）でなく、それよりも低い４Ｎ／ｍｍ２のプレス圧であっても、比較例２と同等の性能を有するストランドボードを成形できることが判る。 And by making the 2nd and 4th strand layers of the 5 strand layers into high-density strand layers, not the high press pressure (8 N / mm 2 ) as in Comparative Example 2, but lower 4N It can be seen that a strand board having performance equivalent to that of Comparative Example 2 can be formed even at a press pressure of / mm 2 .
　（実施例４）
　厚さが０．８ｍｍで、密度が３００～６００ｋｇ／ｍ３のアスペン製の多数のストランドの集合体を積層して５層のストランド層からなる厚さ１３０ｍｍの積層マットを形成した。その５層のストランド層のうち、実施形態２におけるストランドボードの第６例（図８参照）と同様に、積層方向の中間部に位置する第２～第４ストランド層を除く第１及び第５ストランド層のストランドは、通常一般の密度（平均値４１３ｋｇ／ｍ３）のものを用いた。また、第２～第４ストランド層のストランドについては、通常一般よりも密度が高い（平均値１１００ｋｇ／ｍ３）ものを用いた。 Example 4
An aggregate of a large number of strands made of aspen having a thickness of 0.8 mm and a density of 300 to 600 kg / m 3 was laminated to form a laminated mat having a thickness of 130 mm consisting of five strand layers. Of the five strand layers, as in the sixth example of the strand board in the second embodiment (see FIG. 8), the first and fifth strand layers except for the second to fourth strand layers located in the intermediate portion in the stacking direction are used. As the strand of the strand layer, one having a general density (average value 413 kg / m 3 ) was used. In addition, the strands of the second to fourth strand layers used have a higher density than normal (average value 1100 kg / m 3 ).
　その後、プレス温度１６０℃及びプレス圧８Ｎ／ｍｍ２で６０分間の熱圧プレスを行い、所定の密度及び厚さ（図１８参照）のストランドボードを得、それを実施例４とした。 Thereafter, hot pressing was performed at a pressing temperature of 160 ° C. and a pressing pressure of 8 N / mm 2 for 60 minutes to obtain a strand board having a predetermined density and thickness (see FIG. 18).
　（比較例３）
　実施例４と同様にして、５層のストランド層からなる積層マットを形成した。その５層のストランド層は、全て通常一般の密度（平均値４１３ｋｇ／ｍ３）のものを用いた。その後、プレス温度１４０℃及びプレス圧８Ｎ／ｍｍ２で６０分間の熱圧プレスを行い、所定の密度及び厚さ（図１８参照）のストランドボードを得、それを比較例３とした。他の処理は実施例４と同じである。 (Comparative Example 3)
In the same manner as in Example 4, a laminated mat composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 413 kg / m 3 ). Thereafter, a hot press for 60 minutes was performed at a press temperature of 140 ° C. and a press pressure of 8 N / mm 2 to obtain a strand board having a predetermined density and thickness (see FIG. 18). Other processes are the same as those in the fourth embodiment.
　（比較例４）
　実施例４と同様にして、５層のストランド層からなる積層マットを形成した。その５層のストランド層は、全て通常一般の密度（平均値４１３ｋｇ／ｍ３）のものを用いた。その後、プレス温度１６０℃及びプレス圧８Ｎ／ｍｍ２で３０分間の熱圧プレスを行い、所定の密度及び厚さのストランドボードを得、それを比較例４とした。尚、この比較例４では、冬場で接着剤の硬化不良を避けるために、プレス温度を比較例３よりも上げている。また、比較例４は小サイズのものであり、プレス時間を実施例４や比較例３よりも短くしている。他の処理は実施例４と同じである。 (Comparative Example 4)
In the same manner as in Example 4, a laminated mat composed of five strand layers was formed. All of the five strand layers were of ordinary density (average value 413 kg / m 3 ). Thereafter, hot pressing for 30 minutes at a pressing temperature of 160 ° C. and a pressing pressure of 8 N / mm 2 was performed to obtain a strand board having a predetermined density and thickness. In Comparative Example 4, the press temperature is higher than that of Comparative Example 3 in order to avoid poor curing of the adhesive in winter. Comparative Example 4 is of a small size, and the pressing time is shorter than that of Example 4 or Comparative Example 3. Other processes are the same as those in the fourth embodiment.
　（試験Ｃ）
　上記実施例４及び比較例３について常態曲げ試験、煮沸試験及び接合耐久性試験（Bond Durabirity試験）を行った。その結果を他の物性と共に図１８に示す。尚、図１８中、「Elastic Limit Pmax」は弾性限界荷重、「Ratio of ELP」は最大荷重（Pmax）に占めるElastic Limit Pmaxの割合、「Inside Share Strength」は内部剪断破壊強度である。また、曲げ方向の「縦」とはボードの長さ方向を、また曲げ方向の「横」とはボードの幅方向をそれぞれ表し、「Ｎ＝２（Ｎ＝３）」とは試験片数が２体（３体）であることを表している。また、「ＴＳ」は厚さ膨潤率、「ＷＡ」は吸水率、「ＩＢ」は剥離強度である。 (Test C)
About the said Example 4 and the comparative example 3, the normal bending test, the boiling test, and the joining durability test (Bond Durabirity test) were done. The results are shown in FIG. 18 together with other physical properties. In FIG. 18, “Elastic Limit Pmax” is the elastic limit load, “Ratio of ELP” is the ratio of Elastic Limit Pmax to the maximum load (Pmax), and “Inside Share Strength” is the internal shear fracture strength. “Vertical” in the bending direction represents the length direction of the board, “Horizontal” in the bending direction represents the width direction of the board, and “N = 2 (N = 3)” represents the number of test pieces. It represents that it is 2 bodies (3 bodies). “TS” is the thickness swelling rate, “WA” is the water absorption rate, and “IB” is the peel strength.
　また、実施例４及び比較例４について釘引き抜き試験を行った。釘引き抜き試験では、実施例４及び比較例４の各サンプルに形成される先孔は２ｍｍの内径で深さ２５ｍｍである。また、実施例４は３つのサンプルを、また比較例４は４つのサンプルをそれぞれ試験し、それらの平均値を求めた。その結果を図１９に示す。 In addition, a nail pull-out test was performed on Example 4 and Comparative Example 4. In the nail pull-out test, the tip hole formed in each sample of Example 4 and Comparative Example 4 has an inner diameter of 2 mm and a depth of 25 mm. Moreover, Example 4 tested 3 samples, and the comparative example 4 tested 4 samples, respectively, and calculated | required the average value. The result is shown in FIG.
　また、試験Ａと同様に、密度分布測定装置を用いて、ストランドボードの厚さ方向（積層方向）の密度分布を測定した結果を図２０に示す。 Also, as in Test A, the result of measuring the density distribution in the thickness direction (stacking direction) of the strand board using a density distribution measuring device is shown in FIG.
　図１８の結果を考察するに、５層のストランド層のうちの積層方向中間部に位置する第２～第４ストランド層を高密度ストランド層とした実施例４と、５層の全層を低密度ストランド層とした比較例３とを比較したとき、実施例４の曲げ強度は比較例３と同程度であり、実施例４の煮沸試験後の剥離強度は比較例３を上回っている。 Considering the result of FIG. 18, in Example 4 in which the second to fourth strand layers located in the middle portion in the stacking direction of the five strand layers are high-density strand layers, all the five layers are reduced. When compared with Comparative Example 3 in which the density strand layer was compared, the bending strength of Example 4 was almost the same as that of Comparative Example 3, and the peel strength after the boiling test of Example 4 was higher than that of Comparative Example 3.
　このため、５層のストランド層のうちの第２～第４ストランド層を高密度ストランド層とすることで、比較例３と同等の性能を有するストランドボードを成形できることが判る。 Therefore, it can be seen that a strand board having the same performance as that of Comparative Example 3 can be formed by making the second to fourth strand layers of the five strand layers into high-density strand layers.
　また、図１９の結果を考察すると、５層のストランド層のうちの厚さ方向中間部に位置する第２～第４ストランド層を高密度ストランド層とすれば、釘引き抜き抵抗（力）を増大させて、同性能の向上を達成できることが判る。 Further, considering the results of FIG. 19, the nail pulling resistance (force) is increased if the second to fourth strand layers located in the middle in the thickness direction of the five strand layers are high-density strand layers. It can be seen that the same performance improvement can be achieved.
　本発明は、コンテナ、船舶、車両用等の床材として用いるのに好適である。また、住宅等建築物の床材、耐力面材として用いるのに好適な新しい建築用材としても極めて有用であり、産業上の利用可能性が高い。 The present invention is suitable for use as a flooring material for containers, ships, vehicles and the like. In addition, it is extremely useful as a new building material suitable for use as a flooring material and load bearing surface material for buildings such as houses, and has high industrial applicability.
　Ｂ　ストランドボード（木質積層材）
　１　ストランド層（木質材層）
　１ａ　高密度ストランド層（高密度木質材層）
　１ｂ　低密度ストランド層（低密度木質材層）
　５　ストランド（切削片） B Strand board (wood laminate)
1 Strand layer (wooden material layer)
1a High-density strand layer (high-density wood material layer)
1b Low density strand layer (low density wood layer)
5 Strand (cutting piece)

Claims (13)

  1. 　各々、集合状態の複数の切削片からなる木質材又は単板からなる木質材で構成された複数の木質材層が積層された状態で一体化された木質積層材であって、
    　上記木質材層の積層方向の密度分布が実質的に一定であることを特徴とする木質積層材。     Each is a wood laminate made by integrating a plurality of wood layers composed of a wood material consisting of a plurality of cutting pieces in a collective state or a wood material consisting of a single plate,
    A wood laminate material characterized in that the density distribution in the laminate direction of the wood material layer is substantially constant.
  2. 　請求項１において、
    　木質材の密度は、３００ｋｇ／ｍ３以上かつ１１００ｋｇ／ｍ３以下であることを特徴とする木質積層材。     In claim 1,
    The density of the wood material is 300 kg / m 3 or more and 1100 kg / m 3 or less.
  3. 　請求項１又は２において、
    　複数の木質材層の厚さは、積層方向の内側から外側に向かって次第に厚さが増していることを特徴とする木質積層材。     In claim 1 or 2,
    A thickness of the plurality of wood material layers is gradually increased from the inside to the outside in the lamination direction.
  4. 　各々、集合状態の複数の切削片からなる木質材又は単板からなる木質材で構成された複数の木質材層が積層された状態で一体化された木質積層材であって、
    　上記複数の木質材層は、他の木質材層よりも密度の高い少なくとも１層の高密度木質材層と、上記他の木質材層からなる低密度木質材層とを備えていることを特徴とする木質積層材。     Each is a wood laminate made by integrating a plurality of wood layers composed of a wood material consisting of a plurality of cutting pieces in a collective state or a wood material consisting of a single plate,
    The plurality of wood material layers includes at least one high-density wood material layer having a higher density than other wood material layers, and a low-density wood material layer composed of the other wood material layers. Wood laminate material.
  5. 　請求項４において、
    　木質材層の積層方向両端部に位置する木質材層が高密度木質材層とされていることを特徴とする木質積層材。     In claim 4,
    A wood laminate characterized in that the wood material layers located at both ends of the wood material layer in the laminating direction are high-density wood material layers.
  6. 　請求項４において、
    　木質材層の積層方向中間部に位置する木質材層が高密度木質材層とされていることを特徴とする木質積層材。     In claim 4,
    A wood laminate material characterized in that the wood material layer located in the intermediate direction of the wood material layer is a high-density wood material layer.
  7. 　請求項４において、
    　木質材層の積層方向両端部及び中央部を除いた部分に位置する木質材層が高密度木質材層とされていることを特徴とする木質積層材。     In claim 4,
    A wood laminate material, characterized in that the wood material layer located in a portion excluding both ends and the central portion of the wood material layer in the lamination direction is a high-density wood material layer.
  8. 　請求項１～７のいずれか１つにおいて、
    　各木質材層における木質材の繊維が互いに同じ方向に延び、
    　隣接する木質材層の木質材の繊維は、互いに交差する方向又は平行な方向に延びていることを特徴とする木質積層材。     In any one of claims 1 to 7,
    The wood fibers in each wood layer extend in the same direction,
    A wood laminate, wherein the fibers of the wood material adjacent to each other extend in a direction intersecting or parallel to each other.
  9. 　請求項１～８のいずれか１つにおいて、
    　複数の木質材層のうちの表面層及び裏面層における木質材の繊維が互いに同じ方向に延びていることを特徴とする木質積層材。     Any one of claims 1 to 8,
    A wood laminate, wherein the fibers of the wood material in the front surface layer and the back surface layer of the plurality of wood material layers extend in the same direction.
  10. 　請求項１～９のいずれか１つにおいて、
    　木質材層の積層数は奇数であることを特徴とする木質積層材。     In any one of claims 1 to 9,
    A wood laminate material characterized in that the number of wood material layers is an odd number.
  11. 　請求項１～１０のいずれか１つにおいて、
    　複数の木質材層は、該複数の木質材層による密度の分布が積層方向の中央位置に対し面対称になるように積層されていることを特徴とする木質積層材。     In any one of claims 1 to 10,
    A plurality of wood material layers are laminated so that a density distribution by the plurality of wood material layers is plane-symmetric with respect to a central position in a lamination direction.
  12. 　請求項１～１１のいずれか１つにおいて、
    　木質材は、切削片からなるストランドであることを特徴とする木質積層材。     In any one of claims 1 to 11,
    A wooden material, wherein the wooden material is a strand made of a cut piece.
  13. 　木質積層材の製造方法であって、
    　切削片又は単板からなる複数の木質材を積み重ねることで、複数の木質材層を、少なくとも１つの木質材層の木質材が他の木質材層よりも相対的に密度の高い木質材で構成されるように形成する積層工程と、
    　上記積層工程で形成された複数の木質材層を一体的に成形する成形工程とを備えていることを特徴とする木質積層材の製造方法。     A method for manufacturing a wood laminate,
    By stacking a plurality of wood materials consisting of cutting pieces or single plates, a plurality of wood material layers are composed of a wood material in which at least one wood material layer has a relatively higher density than other wood material layers Laminating step to be formed,
    And a molding step for integrally molding a plurality of wood layers formed in the above-described lamination step.
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